diff --git a/examples/example-gateway/build/gen-code/clients/bar/bar/bar.go b/examples/example-gateway/build/gen-code/clients/bar/bar/bar.go
index 525946d86..bca969bc4 100644
--- a/examples/example-gateway/build/gen-code/clients/bar/bar/bar.go
+++ b/examples/example-gateway/build/gen-code/clients/bar/bar/bar.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package bar
diff --git a/examples/example-gateway/build/gen-code/clients/bar/bar/bar_easyjson.go b/examples/example-gateway/build/gen-code/clients/bar/bar/bar_easyjson.go
index bdf663401..299029a92 100644
--- a/examples/example-gateway/build/gen-code/clients/bar/bar/bar_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/bar/bar/bar_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : yvRopgBzY9ScvsC/nz0ERw==
+// Checksum : b5X7Uh5iRP/sgSQXJo5GFQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package bar
@@ -71,12 +71,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"Key\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Key))
 	}
 	{
 		const prefix string = ",\"Value\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Value == nil {
 			out.RawString("null")
 		} else {
@@ -156,7 +166,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"Key\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Key == nil {
 			out.RawString("null")
 		} else {
@@ -165,7 +180,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"Value\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Value))
 	}
 	out.RawByte('}')
@@ -249,8 +269,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Request1 != nil {
 		const prefix string = ",\"request1\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Request1).MarshalEasyJSON(out)
 	}
 	if in.Request2 != nil {
@@ -386,27 +410,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	{
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Count))
 	}
 	if in.OptCount != nil {
 		const prefix string = ",\"optCount\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.OptCount))
 	}
 	{
 		const prefix string = ",\"foos\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foos == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -543,27 +592,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	{
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Count))
 	}
 	if in.OptCount != nil {
 		const prefix string = ",\"optCount\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.OptCount))
 	}
 	{
 		const prefix string = ",\"foos\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foos == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -703,27 +777,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if in.AuthUUID != nil {
 		const prefix string = ",\"authUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID))
 	}
 	if in.AuthUUID2 != nil {
 		const prefix string = ",\"authUUID2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID2))
 	}
 	{
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foo == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -835,22 +934,42 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if in.AuthUUID != nil {
 		const prefix string = ",\"authUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID))
 	}
 	if in.AuthUUID2 != nil {
 		const prefix string = ",\"authUUID2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID2))
 	}
 	out.RawByte('}')
@@ -921,7 +1040,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.UserUUID))
 	}
 	out.RawByte('}')
@@ -995,8 +1119,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -1067,7 +1195,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Arg))
 	}
 	out.RawByte('}')
@@ -1162,8 +1295,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v11, v12 := range in.Success {
@@ -1276,7 +1413,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -1387,8 +1529,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v17, v18 := range in.Success {
@@ -1479,7 +1625,12 @@ func easyjson4347b5c1Encode(out *jwriter.Writer, in struct {
 	_ = first
 	{
 		const prefix string = ",\"Key\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Key == nil {
 			out.RawString("null")
 		} else {
@@ -1488,7 +1639,12 @@ func easyjson4347b5c1Encode(out *jwriter.Writer, in struct {
 	}
 	{
 		const prefix string = ",\"Value\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Value))
 	}
 	out.RawByte('}')
@@ -1565,7 +1721,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -1671,8 +1832,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v23, v24 := range in.Success {
@@ -1785,7 +1950,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -1874,8 +2044,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -1946,7 +2120,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Arg))
 	}
 	out.RawByte('}')
@@ -2030,8 +2209,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v29First := true
@@ -2169,7 +2352,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -2277,8 +2465,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v33First := true
@@ -2393,7 +2585,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -2500,8 +2697,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v37, v38 := range in.Success {
@@ -2602,11 +2803,16 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
-		if in.Arg == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
-			out.RawString("null")
-		} else {
-			out.RawByte('[')
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
+		if in.Arg == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
+			out.RawString("null")
+		} else {
+			out.RawByte('[')
 			for v40, v41 := range in.Arg {
 				if v40 > 0 {
 					out.RawByte(',')
@@ -2687,8 +2893,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(*in.Success))
 	}
 	out.RawByte('}')
@@ -2759,7 +2969,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(in.Arg))
 	}
 	out.RawByte('}')
@@ -2833,8 +3048,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(*in.Success))
 	}
 	out.RawByte('}')
@@ -2905,7 +3124,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(in.Arg))
 	}
 	out.RawByte('}')
@@ -2979,8 +3203,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.Success))
 	}
 	out.RawByte('}')
@@ -3051,7 +3279,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Arg))
 	}
 	out.RawByte('}')
@@ -3143,8 +3376,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v43First := true
@@ -3259,7 +3496,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -3353,8 +3595,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.Success))
 	}
 	out.RawByte('}')
@@ -3425,7 +3671,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(in.Arg))
 	}
 	out.RawByte('}')
@@ -3501,8 +3752,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.Success).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -3578,8 +3833,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Arg != nil {
 		const prefix string = ",\"arg\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.Arg).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -3653,8 +3912,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.Success))
 	}
 	out.RawByte('}')
@@ -3725,7 +3988,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(in.Arg))
 	}
 	out.RawByte('}')
@@ -3799,8 +4067,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.Success))
 	}
 	out.RawByte('}')
@@ -3871,7 +4143,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.Arg))
 	}
 	out.RawByte('}')
@@ -3942,8 +4219,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Success) != 0 {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.Success)
 	}
 	out.RawByte('}')
@@ -4019,7 +4300,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.Arg)
 	}
 	out.RawByte('}')
@@ -4113,8 +4399,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -4205,7 +4495,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"teapot\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Teapot))
 	}
 	out.RawByte('}')
@@ -4270,7 +4565,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -4279,7 +4579,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Foo != nil {
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCodeClientsFooFoo1(out, *in.Foo)
 	}
 	out.RawByte('}')
@@ -4420,32 +4725,62 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"fooString\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.FooString))
 	}
 	if in.FooI32 != nil {
 		const prefix string = ",\"fooI32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.FooI32))
 	}
 	if in.FooI16 != nil {
 		const prefix string = ",\"fooI16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.FooI16))
 	}
 	if in.FooDouble != nil {
 		const prefix string = ",\"fooDouble\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.FooDouble))
 	}
 	if in.FooBool != nil {
 		const prefix string = ",\"fooBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.FooBool))
 	}
 	if len(in.FooMap) != 0 {
 		const prefix string = ",\"fooMap\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v53First := true
@@ -4464,7 +4799,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Message != nil {
 		const prefix string = ",\"message\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCodeClientsFooBaseBase(out, *in.Message)
 	}
 	out.RawByte('}')
@@ -4511,7 +4851,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"body\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Body))
 	}
 	out.RawByte('}')
@@ -4571,8 +4916,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -4661,7 +5010,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -4749,8 +5103,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -4839,7 +5197,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -4927,8 +5290,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -5081,8 +5448,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -5235,8 +5606,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	if in.BarException != nil {
@@ -5350,7 +5725,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"demoIds\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.DemoIds == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -5366,7 +5746,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.DemoType != nil {
 		const prefix string = ",\"demoType\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.DemoType).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -5450,8 +5835,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	if in.BarException != nil {
@@ -5660,12 +6049,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"filter\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Filter))
 	}
 	if in.Count != nil {
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.Count))
 	}
 	out.RawByte('}')
@@ -5795,7 +6194,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.UserUUID))
 	}
 	out.RawByte('}')
@@ -5869,8 +6273,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -5959,7 +6367,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -5968,7 +6381,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Opt != nil {
 		const prefix string = ",\"opt\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Opt).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6042,8 +6460,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6175,17 +6597,32 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if len(in.Foo) != 0 {
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v59, v60 := range in.Foo {
@@ -6199,7 +6636,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"bar\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Bar == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -6284,8 +6726,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6359,8 +6805,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	out.RawByte('}')
@@ -6434,8 +6884,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6516,12 +6970,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"uuid\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.UUID))
 	}
 	if in.Params != nil {
 		const prefix string = ",\"params\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Params).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6595,8 +7059,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6682,7 +7150,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -6691,7 +7164,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"entityUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.EntityUUID))
 	}
 	out.RawByte('}')
@@ -6765,8 +7243,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6855,7 +7337,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -6864,7 +7351,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Opt != nil {
 		const prefix string = ",\"opt\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Opt).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -6938,8 +7430,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -7313,87 +7809,172 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"aStr\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AStr))
 	}
 	if in.AnOptStr != nil {
 		const prefix string = ",\"anOptStr\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AnOptStr))
 	}
 	{
 		const prefix string = ",\"aBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.ABool))
 	}
 	if in.AnOptBool != nil {
 		const prefix string = ",\"anOptBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.AnOptBool))
 	}
 	{
 		const prefix string = ",\"aInt8\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(in.AInt8))
 	}
 	if in.AnOptInt8 != nil {
 		const prefix string = ",\"anOptInt8\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(*in.AnOptInt8))
 	}
 	{
 		const prefix string = ",\"aInt16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(in.AInt16))
 	}
 	if in.AnOptInt16 != nil {
 		const prefix string = ",\"anOptInt16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.AnOptInt16))
 	}
 	{
 		const prefix string = ",\"aInt32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.AInt32))
 	}
 	if in.AnOptInt32 != nil {
 		const prefix string = ",\"anOptInt32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.AnOptInt32))
 	}
 	{
 		const prefix string = ",\"aInt64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(in.AInt64))
 	}
 	if in.AnOptInt64 != nil {
 		const prefix string = ",\"anOptInt64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(*in.AnOptInt64))
 	}
 	{
 		const prefix string = ",\"aFloat64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(in.AFloat64))
 	}
 	if in.AnOptFloat64 != nil {
 		const prefix string = ",\"anOptFloat64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.AnOptFloat64))
 	}
 	{
 		const prefix string = ",\"aUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AUUID))
 	}
 	if in.AnOptUUID != nil {
 		const prefix string = ",\"anOptUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AnOptUUID))
 	}
 	{
 		const prefix string = ",\"aListUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AListUUID == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -7409,7 +7990,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptListUUID) != 0 {
 		const prefix string = ",\"anOptListUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v71, v72 := range in.AnOptListUUID {
@@ -7423,7 +8009,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aStringList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AStringList == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -7439,7 +8030,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptStringList) != 0 {
 		const prefix string = ",\"anOptStringList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v75, v76 := range in.AnOptStringList {
@@ -7453,7 +8049,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aUUIDList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AUUIDList == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -7469,7 +8070,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptUUIDList) != 0 {
 		const prefix string = ",\"anOptUUIDList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v79, v80 := range in.AnOptUUIDList {
@@ -7483,12 +8089,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aTs\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.ATs).MarshalJSON())
 	}
 	if in.AnOptTs != nil {
 		const prefix string = ",\"anOptTs\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.AnOptTs).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -7562,8 +8178,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -7696,8 +8316,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.BarException != nil {
 		const prefix string = ",\"barException\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.BarException).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -7768,7 +8392,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Request))
 	}
 	out.RawByte('}')
@@ -7867,7 +8496,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"nodes\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Nodes == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -7883,7 +8517,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"height\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Height))
 	}
 	out.RawByte('}')
@@ -8040,22 +8679,42 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	{
 		const prefix string = ",\"intWithRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.IntWithRange))
 	}
 	{
 		const prefix string = ",\"intWithoutRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.IntWithoutRange))
 	}
 	{
 		const prefix string = ",\"mapIntWithRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.MapIntWithRange == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -8076,7 +8735,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"mapIntWithoutRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.MapIntWithoutRange == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -8097,12 +8761,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"binaryField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.BinaryField)
 	}
 	if in.NextResponse != nil {
 		const prefix string = ",\"nextResponse\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.NextResponse).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -8183,12 +8857,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.Recur != nil {
 		const prefix string = ",\"recur\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Recur).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -8305,32 +8989,62 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	{
 		const prefix string = ",\"boolField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.BoolField))
 	}
 	{
 		const prefix string = ",\"binaryField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.BinaryField)
 	}
 	{
 		const prefix string = ",\"timestamp\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.Timestamp).MarshalJSON())
 	}
 	{
 		const prefix string = ",\"enumField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.EnumField).MarshalJSON())
 	}
 	{
 		const prefix string = ",\"longField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.LongField).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -8401,7 +9115,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/baz/base/base.go b/examples/example-gateway/build/gen-code/clients/baz/base/base.go
index 4ee8199f2..16dfa4a53 100644
--- a/examples/example-gateway/build/gen-code/clients/baz/base/base.go
+++ b/examples/example-gateway/build/gen-code/clients/baz/base/base.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package base
diff --git a/examples/example-gateway/build/gen-code/clients/baz/baz/baz.go b/examples/example-gateway/build/gen-code/clients/baz/baz/baz.go
index b2a592d8a..5ff3db320 100644
--- a/examples/example-gateway/build/gen-code/clients/baz/baz/baz.go
+++ b/examples/example-gateway/build/gen-code/clients/baz/baz/baz.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package baz
diff --git a/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts.go b/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts.go
index 81e4b6607..181283d30 100644
--- a/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts.go
+++ b/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package contacts
diff --git a/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts_easyjson.go b/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts_easyjson.go
index 7388a9e5b..1f3d44160 100644
--- a/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/contacts/contacts/contacts_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 5B3Pt2UTYZL+5sNN7af0Nw==
+// Checksum : GhXzO/TNdL2KyCWoD2kcAg==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package contacts
@@ -159,12 +159,22 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.UserUUID))
 	}
 	{
 		const prefix string = ",\"contacts\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Contacts == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -253,8 +263,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -387,8 +401,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -467,7 +485,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"saveContactsRequest\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.SaveContactsRequest == nil {
 			out.RawString("null")
 		} else {
@@ -555,8 +578,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Type != nil {
 		const prefix string = ",\"type\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Type))
 	}
 	if in.Text != nil {
@@ -760,8 +787,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.FirstName != nil {
 		const prefix string = ",\"firstName\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.FirstName))
 	}
 	if in.LastName != nil {
@@ -986,8 +1017,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Fragments) != 0 {
 		const prefix string = ",\"fragments\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v5, v6 := range in.Fragments {
diff --git a/examples/example-gateway/build/gen-code/clients/corge/corge/corge.go b/examples/example-gateway/build/gen-code/clients/corge/corge/corge.go
index 30b0fd196..a6b324a5b 100644
--- a/examples/example-gateway/build/gen-code/clients/corge/corge/corge.go
+++ b/examples/example-gateway/build/gen-code/clients/corge/corge/corge.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package corge
diff --git a/examples/example-gateway/build/gen-code/clients/corge/corge/corge_easyjson.go b/examples/example-gateway/build/gen-code/clients/corge/corge/corge_easyjson.go
index adaf9d95f..0090d122d 100644
--- a/examples/example-gateway/build/gen-code/clients/corge/corge/corge_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/corge/corge/corge_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : +efygMU8FfaaZUS1Sb3saQ==
+// Checksum : tUaL5uh/EuXE1lehxKG0mQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package corge
@@ -67,8 +67,12 @@ func easyjsonAbe23ddeEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -139,7 +143,12 @@ func easyjsonAbe23ddeEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Arg))
 	}
 	out.RawByte('}')
@@ -213,8 +222,12 @@ func easyjsonAbe23ddeEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.Success))
 	}
 	out.RawByte('}')
@@ -285,7 +298,12 @@ func easyjsonAbe23ddeEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.Arg))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/foo/base/base/base.go b/examples/example-gateway/build/gen-code/clients/foo/base/base/base.go
index 6dd9b41f0..8177eeda7 100644
--- a/examples/example-gateway/build/gen-code/clients/foo/base/base/base.go
+++ b/examples/example-gateway/build/gen-code/clients/foo/base/base/base.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package base
diff --git a/examples/example-gateway/build/gen-code/clients/foo/base/base/base_easyjson.go b/examples/example-gateway/build/gen-code/clients/foo/base/base/base_easyjson.go
index a78f9d1e1..f645e8379 100644
--- a/examples/example-gateway/build/gen-code/clients/foo/base/base/base_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/foo/base/base/base_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 8YzqSOnHguNVcAdG9DpGwQ==
+// Checksum : kOr5FE+JQZqCoXhqQKQSwA==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package base
@@ -64,7 +64,12 @@ func easyjson25720c23EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"body\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Body))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/foo/foo/foo.go b/examples/example-gateway/build/gen-code/clients/foo/foo/foo.go
index 59fcc7cf3..bc4d6ee0f 100644
--- a/examples/example-gateway/build/gen-code/clients/foo/foo/foo.go
+++ b/examples/example-gateway/build/gen-code/clients/foo/foo/foo.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package foo
diff --git a/examples/example-gateway/build/gen-code/clients/foo/foo/foo_easyjson.go b/examples/example-gateway/build/gen-code/clients/foo/foo/foo_easyjson.go
index 36c637717..f81bb1730 100644
--- a/examples/example-gateway/build/gen-code/clients/foo/foo/foo_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/foo/foo/foo_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 1xLf8GA4y5md2Nvz+7yYzg==
+// Checksum : AVnsBqDmcUDxMS4iumUCVA==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package foo
@@ -135,32 +135,62 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"fooString\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.FooString))
 	}
 	if in.FooI32 != nil {
 		const prefix string = ",\"fooI32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.FooI32))
 	}
 	if in.FooI16 != nil {
 		const prefix string = ",\"fooI16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.FooI16))
 	}
 	if in.FooDouble != nil {
 		const prefix string = ",\"fooDouble\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.FooDouble))
 	}
 	if in.FooBool != nil {
 		const prefix string = ",\"fooBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.FooBool))
 	}
 	if len(in.FooMap) != 0 {
 		const prefix string = ",\"fooMap\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v2First := true
@@ -179,7 +209,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Message != nil {
 		const prefix string = ",\"message\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Message).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -253,8 +288,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Name != nil {
 		const prefix string = ",\"name\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Name))
 	}
 	out.RawByte('}')
@@ -325,7 +364,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"teapot\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Teapot))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow.go b/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow.go
index b4b55c984..a163fb3dc 100644
--- a/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow.go
+++ b/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package googlenow
diff --git a/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow_easyjson.go b/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow_easyjson.go
index f774d65cf..1071bee2a 100644
--- a/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/googlenow/googlenow/googlenow_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : bpbC6E/fg9UWEqM0jkRsZQ==
+// Checksum : bf66iX7QoNRm/wUusZxtvQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package googlenow
@@ -241,7 +241,12 @@ func easyjson25b7f9c9EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"authCode\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AuthCode))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/multi/multi/multi.go b/examples/example-gateway/build/gen-code/clients/multi/multi/multi.go
index 9a6359415..078097b56 100644
--- a/examples/example-gateway/build/gen-code/clients/multi/multi/multi.go
+++ b/examples/example-gateway/build/gen-code/clients/multi/multi/multi.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package multi
diff --git a/examples/example-gateway/build/gen-code/clients/multi/multi/multi_easyjson.go b/examples/example-gateway/build/gen-code/clients/multi/multi/multi_easyjson.go
index 34161eb06..7b8d56906 100644
--- a/examples/example-gateway/build/gen-code/clients/multi/multi/multi_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/multi/multi/multi_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : mU8L5hDMgrQxnDNQcm7NEQ==
+// Checksum : sWgi+fkC4XAzevu+9vNmUg==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package multi
@@ -66,8 +66,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -200,8 +204,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -334,8 +342,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions.go b/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions.go
index fa2323728..3204bffc7 100644
--- a/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions.go
+++ b/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package withexceptions
diff --git a/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions_easyjson.go b/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions_easyjson.go
index aec6d3648..b6721fd11 100644
--- a/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions_easyjson.go
+++ b/examples/example-gateway/build/gen-code/clients/withexceptions/withexceptions/withexceptions_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : lxF6JdQdFlGelXNxJn939g==
+// Checksum : D5mK5GMsCL8+xxGPoeoKzg==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package withexceptions
@@ -87,8 +87,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.E1 != nil {
@@ -297,7 +301,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message2\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message2))
 	}
 	out.RawByte('}')
@@ -368,7 +377,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message1))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/app/demo/endpoints/abc/abc.go b/examples/example-gateway/build/gen-code/endpoints/app/demo/endpoints/abc/abc.go
index c130a13c4..d5e71cb09 100644
--- a/examples/example-gateway/build/gen-code/endpoints/app/demo/endpoints/abc/abc.go
+++ b/examples/example-gateway/build/gen-code/endpoints/app/demo/endpoints/abc/abc.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package abc
diff --git a/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar.go b/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar.go
index 57ae7a821..21533f9d2 100644
--- a/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar.go
+++ b/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package bar
diff --git a/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar_easyjson.go
index 3eee7c992..faca5ee61 100644
--- a/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/bar/bar/bar_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 676V+FkOIVlr7ZG4QaOMiw==
+// Checksum : TX5y//rCD5kX8P3NgRGplQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package bar
@@ -79,8 +79,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Request1 != nil {
 		const prefix string = ",\"request1\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Request1).MarshalEasyJSON(out)
 	}
 	if in.Request2 != nil {
@@ -216,27 +220,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	{
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Count))
 	}
 	if in.OptCount != nil {
 		const prefix string = ",\"optCount\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.OptCount))
 	}
 	{
 		const prefix string = ",\"foos\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foos == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -373,27 +402,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	{
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.Count))
 	}
 	if in.OptCount != nil {
 		const prefix string = ",\"optCount\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.OptCount))
 	}
 	{
 		const prefix string = ",\"foos\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foos == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -533,27 +587,52 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if in.AuthUUID != nil {
 		const prefix string = ",\"authUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID))
 	}
 	if in.AuthUUID2 != nil {
 		const prefix string = ",\"authUUID2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID2))
 	}
 	{
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Foo == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -665,22 +744,42 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if in.AuthUUID != nil {
 		const prefix string = ",\"authUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID))
 	}
 	if in.AuthUUID2 != nil {
 		const prefix string = ",\"authUUID2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AuthUUID2))
 	}
 	out.RawByte('}')
@@ -833,8 +932,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -925,7 +1028,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"teapot\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Teapot))
 	}
 	out.RawByte('}')
@@ -990,7 +1098,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -999,7 +1112,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Foo != nil {
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCodeEndpointsFooFoo1(out, *in.Foo)
 	}
 	out.RawByte('}')
@@ -1140,32 +1258,62 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"fooString\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.FooString))
 	}
 	if in.FooI32 != nil {
 		const prefix string = ",\"fooI32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.FooI32))
 	}
 	if in.FooI16 != nil {
 		const prefix string = ",\"fooI16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.FooI16))
 	}
 	if in.FooDouble != nil {
 		const prefix string = ",\"fooDouble\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.FooDouble))
 	}
 	if in.FooBool != nil {
 		const prefix string = ",\"fooBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.FooBool))
 	}
 	if len(in.FooMap) != 0 {
 		const prefix string = ",\"fooMap\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v11First := true
@@ -1184,7 +1332,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Message != nil {
 		const prefix string = ",\"message\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCodeEndpointsFooBaseBase(out, *in.Message)
 	}
 	out.RawByte('}')
@@ -1231,7 +1384,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"body\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Body))
 	}
 	out.RawByte('}')
@@ -1291,8 +1449,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -1381,7 +1543,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -1469,8 +1636,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -1623,8 +1794,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.BarException != nil {
@@ -1777,8 +1952,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	if in.BarException != nil {
@@ -1892,7 +2071,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"demoIds\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.DemoIds == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -1908,7 +2092,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.DemoType != nil {
 		const prefix string = ",\"demoType\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.DemoType).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -1992,8 +2181,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	if in.BarException != nil {
@@ -2202,12 +2395,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"filter\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Filter))
 	}
 	if in.Count != nil {
 		const prefix string = ",\"count\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.Count))
 	}
 	out.RawByte('}')
@@ -2281,12 +2484,16 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
-		(*in.Success).MarshalEasyJSON(out)
-	}
-	out.RawByte('}')
-}
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
+		(*in.Success).MarshalEasyJSON(out)
+	}
+	out.RawByte('}')
+}
 
 // MarshalJSON supports json.Marshaler interface
 func (v Bar_ArgWithUntaggedNestedQueryParams_Result) MarshalJSON() ([]byte, error) {
@@ -2371,7 +2578,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -2380,7 +2592,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Opt != nil {
 		const prefix string = ",\"opt\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Opt).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -2454,8 +2671,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -2587,17 +2808,32 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	if len(in.Foo) != 0 {
 		const prefix string = ",\"foo\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v17, v18 := range in.Foo {
@@ -2611,7 +2847,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"bar\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Bar == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -2696,8 +2937,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -2771,8 +3016,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.UserUUID != nil {
 		const prefix string = ",\"userUUID\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.UserUUID))
 	}
 	out.RawByte('}')
@@ -2846,8 +3095,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -3000,8 +3253,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -3087,7 +3344,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -3096,7 +3358,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"entityUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.EntityUUID))
 	}
 	out.RawByte('}')
@@ -3170,8 +3437,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -3260,7 +3531,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -3269,7 +3545,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Opt != nil {
 		const prefix string = ",\"opt\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Opt).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -3343,8 +3624,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -3718,87 +4003,172 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"aStr\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AStr))
 	}
 	if in.AnOptStr != nil {
 		const prefix string = ",\"anOptStr\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AnOptStr))
 	}
 	{
 		const prefix string = ",\"aBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.ABool))
 	}
 	if in.AnOptBool != nil {
 		const prefix string = ",\"anOptBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.AnOptBool))
 	}
 	{
 		const prefix string = ",\"aInt8\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(in.AInt8))
 	}
 	if in.AnOptInt8 != nil {
 		const prefix string = ",\"anOptInt8\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int8(int8(*in.AnOptInt8))
 	}
 	{
 		const prefix string = ",\"aInt16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(in.AInt16))
 	}
 	if in.AnOptInt16 != nil {
 		const prefix string = ",\"anOptInt16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.AnOptInt16))
 	}
 	{
 		const prefix string = ",\"aInt32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.AInt32))
 	}
 	if in.AnOptInt32 != nil {
 		const prefix string = ",\"anOptInt32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.AnOptInt32))
 	}
 	{
 		const prefix string = ",\"aInt64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(in.AInt64))
 	}
 	if in.AnOptInt64 != nil {
 		const prefix string = ",\"anOptInt64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(*in.AnOptInt64))
 	}
 	{
 		const prefix string = ",\"aFloat64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(in.AFloat64))
 	}
 	if in.AnOptFloat64 != nil {
 		const prefix string = ",\"anOptFloat64\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.AnOptFloat64))
 	}
 	{
 		const prefix string = ",\"aUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AUUID))
 	}
 	if in.AnOptUUID != nil {
 		const prefix string = ",\"anOptUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.AnOptUUID))
 	}
 	{
 		const prefix string = ",\"aListUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AListUUID == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -3814,7 +4184,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptListUUID) != 0 {
 		const prefix string = ",\"anOptListUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v29, v30 := range in.AnOptListUUID {
@@ -3828,7 +4203,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aStringList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AStringList == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -3844,7 +4224,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptStringList) != 0 {
 		const prefix string = ",\"anOptStringList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v33, v34 := range in.AnOptStringList {
@@ -3858,7 +4243,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aUUIDList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.AUUIDList == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -3874,7 +4264,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if len(in.AnOptUUIDList) != 0 {
 		const prefix string = ",\"anOptUUIDList\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v37, v38 := range in.AnOptUUIDList {
@@ -3888,12 +4283,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"aTs\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.ATs).MarshalJSON())
 	}
 	if in.AnOptTs != nil {
 		const prefix string = ",\"anOptTs\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((*in.AnOptTs).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -3967,8 +4372,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -4039,7 +4448,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"name\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Name))
 	}
 	out.RawByte('}')
@@ -4113,8 +4527,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.BarException != nil {
 		const prefix string = ",\"barException\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.BarException).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -4185,7 +4603,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Request))
 	}
 	out.RawByte('}')
@@ -4342,22 +4765,42 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	{
 		const prefix string = ",\"intWithRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.IntWithRange))
 	}
 	{
 		const prefix string = ",\"intWithoutRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.IntWithoutRange))
 	}
 	{
 		const prefix string = ",\"mapIntWithRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.MapIntWithRange == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -4378,7 +4821,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"mapIntWithoutRange\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.MapIntWithoutRange == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -4399,12 +4847,22 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"binaryField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.BinaryField)
 	}
 	if in.NextResponse != nil {
 		const prefix string = ",\"nextResponse\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.NextResponse).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -4521,32 +4979,62 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	{
 		const prefix string = ",\"boolField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.BoolField))
 	}
 	{
 		const prefix string = ",\"binaryField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Base64Bytes(in.BinaryField)
 	}
 	{
 		const prefix string = ",\"timestamp\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.Timestamp).MarshalJSON())
 	}
 	{
 		const prefix string = ",\"enumField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.EnumField).MarshalJSON())
 	}
 	{
 		const prefix string = ",\"longField\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Raw((in.LongField).MarshalJSON())
 	}
 	out.RawByte('}')
@@ -4617,7 +5105,12 @@ func easyjson4347b5c1EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"stringField\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.StringField))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz.go b/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz.go
index aaa207a39..0d7ed9763 100644
--- a/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz.go
+++ b/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package baz
diff --git a/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz_easyjson.go
index 5a0a16942..f65a31fb0 100644
--- a/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/baz/baz/baz_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : f8/G4uzgLYUiBfXwB/ZDdA==
+// Checksum : 0sHopu+qnWuNrO4qbhfPZQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package baz
@@ -89,17 +89,32 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message))
 	}
 	if in.Driver != nil {
 		const prefix string = ",\"driver\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Driver).MarshalEasyJSON(out)
 	}
 	{
 		const prefix string = ",\"rider\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Rider == nil {
 			out.RawString("null")
 		} else {
@@ -374,8 +389,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -484,7 +503,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg1 == nil {
 			out.RawString("null")
 		} else {
@@ -493,7 +517,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Arg2 != nil {
 		const prefix string = ",\"arg2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Arg2).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -587,8 +616,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -687,7 +720,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"req\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Req == nil {
 			out.RawString("null")
 		} else {
@@ -785,8 +823,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -885,7 +927,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"req\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Req == nil {
 			out.RawString("null")
 		} else {
@@ -973,8 +1020,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -1245,8 +1296,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.AuthErr != nil {
 		const prefix string = ",\"authErr\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.AuthErr).MarshalEasyJSON(out)
 	}
 	if in.ServerErr != nil {
@@ -1389,8 +1444,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -1543,8 +1602,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -1643,7 +1706,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"req\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Req == nil {
 			out.RawString("null")
 		} else {
@@ -1731,8 +1799,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -1821,7 +1893,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"request\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Request == nil {
 			out.RawString("null")
 		} else {
@@ -1919,8 +1996,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.AuthErr != nil {
@@ -2034,7 +2115,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg1 == nil {
 			out.RawString("null")
 		} else {
@@ -2043,7 +2129,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"arg2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg2 == nil {
 			out.RawString("null")
 		} else {
@@ -2121,8 +2212,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.AuthErr != nil {
 		const prefix string = ",\"authErr\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.AuthErr).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -2221,7 +2316,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil {
 			out.RawString("null")
 		} else {
@@ -2230,12 +2330,22 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.I64Optional != nil {
 		const prefix string = ",\"i64Optional\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(*in.I64Optional))
 	}
 	if in.TestUUID != nil {
 		const prefix string = ",\"testUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.TestUUID))
 	}
 	out.RawByte('}')
@@ -2309,8 +2419,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.AuthErr != nil {
 		const prefix string = ",\"authErr\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.AuthErr).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -2409,7 +2523,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"arg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Arg == nil {
 			out.RawString("null")
 		} else {
@@ -2418,12 +2537,22 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.I64Optional != nil {
 		const prefix string = ",\"i64Optional\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int64(int64(*in.I64Optional))
 	}
 	if in.TestUUID != nil {
 		const prefix string = ",\"testUUID\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.TestUUID))
 	}
 	out.RawByte('}')
@@ -2494,7 +2623,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message))
 	}
 	out.RawByte('}')
@@ -2565,7 +2699,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"field31\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Field31))
 	}
 	out.RawByte('}')
@@ -2659,7 +2798,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"field21\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Field21 == nil {
 			out.RawString("null")
 		} else {
@@ -2668,7 +2812,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	{
 		const prefix string = ",\"field22\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Field22 == nil {
 			out.RawString("null")
 		} else {
@@ -2769,7 +2918,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"field1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Field1 == nil && (out.Flags&jwriter.NilMapAsEmpty) == 0 {
 			out.RawString(`null`)
 		} else {
@@ -2868,7 +3022,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"recur1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Recur1 == nil {
 			out.RawString("null")
 		} else {
@@ -2943,7 +3102,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message))
 	}
 	out.RawByte('}')
@@ -3024,12 +3188,22 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"msg\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Msg))
 	}
 	if in.Check != nil {
 		const prefix string = ",\"check\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.Check))
 	}
 	out.RawByte('}')
@@ -3188,7 +3362,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"payloads\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Payloads == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -3274,7 +3453,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"target\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Target))
 	}
 	out.RawByte('}')
@@ -3345,7 +3529,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message))
 	}
 	out.RawByte('}')
@@ -3430,17 +3619,32 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"b1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(in.B1))
 	}
 	{
 		const prefix string = ",\"s2\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.S2))
 	}
 	{
 		const prefix string = ",\"i3\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(in.I3))
 	}
 	out.RawByte('}')
@@ -3511,7 +3715,12 @@ func easyjson1bcb5839EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/bounce/bounce/bounce.go b/examples/example-gateway/build/gen-code/endpoints/bounce/bounce/bounce.go
index 9cfac0fe2..6df9f0893 100644
--- a/examples/example-gateway/build/gen-code/endpoints/bounce/bounce/bounce.go
+++ b/examples/example-gateway/build/gen-code/endpoints/bounce/bounce/bounce.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package bounce
diff --git a/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts.go b/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts.go
index 81e4b6607..181283d30 100644
--- a/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts.go
+++ b/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package contacts
diff --git a/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts_easyjson.go
index 7bb912feb..b74956056 100644
--- a/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/contacts/contacts/contacts_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 5B3Pt2UTYZL+5sNN7af0Nw==
+// Checksum : GhXzO/TNdL2KyCWoD2kcAg==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package contacts
@@ -159,12 +159,22 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"userUUID\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.UserUUID))
 	}
 	{
 		const prefix string = ",\"contacts\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.Contacts == nil && (out.Flags&jwriter.NilSliceAsEmpty) == 0 {
 			out.RawString("null")
 		} else {
@@ -253,8 +263,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -387,8 +401,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -467,7 +485,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"saveContactsRequest\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		if in.SaveContactsRequest == nil {
 			out.RawString("null")
 		} else {
@@ -555,8 +578,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Type != nil {
 		const prefix string = ",\"type\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Type))
 	}
 	if in.Text != nil {
@@ -760,8 +787,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.FirstName != nil {
 		const prefix string = ",\"firstName\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.FirstName))
 	}
 	if in.LastName != nil {
@@ -986,8 +1017,12 @@ func easyjson4ee781cfEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if len(in.Fragments) != 0 {
 		const prefix string = ",\"fragments\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('[')
 			for v5, v6 := range in.Fragments {
diff --git a/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base.go b/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base.go
index 6dd9b41f0..8177eeda7 100644
--- a/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base.go
+++ b/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package base
diff --git a/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base_easyjson.go
index cea4f2ca6..1e5a17930 100644
--- a/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/foo/base/base/base_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : 8YzqSOnHguNVcAdG9DpGwQ==
+// Checksum : kOr5FE+JQZqCoXhqQKQSwA==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package base
@@ -64,7 +64,12 @@ func easyjson25720c23EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"body\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Body))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo.go b/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo.go
index bdf08b67e..9e886940b 100644
--- a/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo.go
+++ b/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package foo
diff --git a/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo_easyjson.go
index 6296a9944..c9ba15d55 100644
--- a/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/foo/foo/foo_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : Va8+5d/WHLhmwFWsZBXcLg==
+// Checksum : K9xPh92lZGiQiHuQ2tOnfw==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package foo
@@ -135,32 +135,62 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"fooString\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.FooString))
 	}
 	if in.FooI32 != nil {
 		const prefix string = ",\"fooI32\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int32(int32(*in.FooI32))
 	}
 	if in.FooI16 != nil {
 		const prefix string = ",\"fooI16\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Int16(int16(*in.FooI16))
 	}
 	if in.FooDouble != nil {
 		const prefix string = ",\"fooDouble\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Float64(float64(*in.FooDouble))
 	}
 	if in.FooBool != nil {
 		const prefix string = ",\"fooBool\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.Bool(bool(*in.FooBool))
 	}
 	if len(in.FooMap) != 0 {
 		const prefix string = ",\"fooMap\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		{
 			out.RawByte('{')
 			v2First := true
@@ -179,7 +209,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	}
 	if in.Message != nil {
 		const prefix string = ",\"message\":"
-		out.RawString(prefix)
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Message).MarshalEasyJSON(out)
 	}
 	out.RawByte('}')
@@ -253,8 +288,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Name != nil {
 		const prefix string = ",\"name\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Name))
 	}
 	out.RawByte('}')
@@ -325,7 +364,12 @@ func easyjsonE4de407aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"teapot\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Teapot))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow.go b/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow.go
index 542e39756..43dff79bf 100644
--- a/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow.go
+++ b/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package googlenow
diff --git a/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow_easyjson.go
index fa6814db0..8bf4722a9 100644
--- a/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/googlenow/googlenow/googlenow_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : iUmFXJKFpoMDQA3lFNjA5Q==
+// Checksum : BMMMPFmSVSoxxCNxIw+C+A==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package googlenow
@@ -241,7 +241,12 @@ func easyjson25b7f9c9EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"authCode\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.AuthCode))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/models/meta/meta.go b/examples/example-gateway/build/gen-code/endpoints/models/meta/meta.go
index a2f2531ae..acabe95bd 100644
--- a/examples/example-gateway/build/gen-code/endpoints/models/meta/meta.go
+++ b/examples/example-gateway/build/gen-code/endpoints/models/meta/meta.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package meta
diff --git a/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi.go b/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi.go
index 92d04b37f..1a6c71555 100644
--- a/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi.go
+++ b/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package multi
diff --git a/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi_easyjson.go
index e04802e36..1f500e4da 100644
--- a/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/multi/multi/multi_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : eoFUxn4qjQ852StqmbyKig==
+// Checksum : pmTCG1Dq7lD4AXp+UflKTQ==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package multi
@@ -66,8 +66,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -200,8 +204,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
@@ -334,8 +342,12 @@ func easyjson536f2a59EncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(*in.Success))
 	}
 	out.RawByte('}')
diff --git a/examples/example-gateway/build/gen-code/endpoints/tchannel/baz/baz/baz.go b/examples/example-gateway/build/gen-code/endpoints/tchannel/baz/baz/baz.go
index 2447fb508..6bf229919 100644
--- a/examples/example-gateway/build/gen-code/endpoints/tchannel/baz/baz/baz.go
+++ b/examples/example-gateway/build/gen-code/endpoints/tchannel/baz/baz/baz.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package baz
diff --git a/examples/example-gateway/build/gen-code/endpoints/tchannel/echo/echo/echo.go b/examples/example-gateway/build/gen-code/endpoints/tchannel/echo/echo/echo.go
index 0699fe20c..9f1af2e35 100644
--- a/examples/example-gateway/build/gen-code/endpoints/tchannel/echo/echo/echo.go
+++ b/examples/example-gateway/build/gen-code/endpoints/tchannel/echo/echo/echo.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package echo
diff --git a/examples/example-gateway/build/gen-code/endpoints/tchannel/quux/quux/quux.go b/examples/example-gateway/build/gen-code/endpoints/tchannel/quux/quux/quux.go
index 57766c8a1..2d1f139d9 100644
--- a/examples/example-gateway/build/gen-code/endpoints/tchannel/quux/quux/quux.go
+++ b/examples/example-gateway/build/gen-code/endpoints/tchannel/quux/quux/quux.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package quux
diff --git a/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions.go b/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions.go
index 2f6ec68ee..d6471ec63 100644
--- a/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions.go
+++ b/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions.go
@@ -1,4 +1,4 @@
-// Code generated by thriftrw v1.20.1. DO NOT EDIT.
+// Code generated by thriftrw v1.20.2. DO NOT EDIT.
 // @generated
 
 package withexceptions
diff --git a/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions_easyjson.go b/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions_easyjson.go
index 426ced314..cc8f1b06f 100644
--- a/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions_easyjson.go
+++ b/examples/example-gateway/build/gen-code/endpoints/withexceptions/withexceptions/withexceptions_easyjson.go
@@ -1,6 +1,6 @@
 // Code generated by zanzibar
 // @generated
-// Checksum : OhgaX0m9kQeImpusMlruIw==
+// Checksum : HeeTwmpypP9hgeNn2NZ60g==
 // Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
 
 package withexceptions
@@ -87,8 +87,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	if in.Success != nil {
 		const prefix string = ",\"success\":"
-		first = false
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		(*in.Success).MarshalEasyJSON(out)
 	}
 	if in.E1 != nil {
@@ -297,7 +301,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message2\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message2))
 	}
 	out.RawByte('}')
@@ -368,7 +377,12 @@ func easyjsonD396a41aEncodeGithubComUberZanzibarExamplesExampleGatewayBuildGenCo
 	_ = first
 	{
 		const prefix string = ",\"message1\":"
-		out.RawString(prefix[1:])
+		if first {
+			first = false
+			out.RawString(prefix[1:])
+		} else {
+			out.RawString(prefix)
+		}
 		out.String(string(in.Message1))
 	}
 	out.RawByte('}')