Changes to show the right amount of time (#331)

* Changes to take the correct amount of time
* Returned to origial way to calculate ConnTime and added a new time called TCPConnTime. And changed DNSStart check to inside client trace context.
* Added godoc comment to TCPConnTime
* Capitalized TCP and added ending period

request.go

@@ -568,6 +568,7 @@ func (r *Request) TraceInfo() TraceInfo {
 	return TraceInfo{
 		DNSLookup:     ct.dnsDone.Sub(ct.dnsStart),
 		ConnTime:      ct.gotConn.Sub(ct.getConn),
+		TCPConnTime:   ct.connectDone.Sub(ct.dnsDone),
 		TLSHandshake:  ct.tlsHandshakeDone.Sub(ct.tlsHandshakeStart),
 		ServerTime:    ct.gotFirstResponseByte.Sub(ct.gotConn),
 		ResponseTime:  ct.endTime.Sub(ct.gotFirstResponseByte),

trace.go

@@ -27,6 +27,9 @@ type TraceInfo struct {
 	// ConnTime is a duration that took to obtain a successful connection.
 	ConnTime time.Duration
 
+	// TCPConnTime is a duration that took to obtain the TCP connection.
+	TCPConnTime time.Duration
+
 	// TLSHandshake is a duration that TLS handshake took place.
 	TLSHandshake time.Duration
 
@@ -63,6 +66,7 @@ type TraceInfo struct {
 type clientTrace struct {
 	getConn              time.Time
 	gotConn              time.Time
+	connectDone          time.Time
 	gotFirstResponseByte time.Time
 	dnsStart             time.Time
 	dnsDone              time.Time
@@ -86,14 +90,19 @@ func (t *clientTrace) createContext(ctx context.Context) context.Context {
 			DNSDone: func(_ httptrace.DNSDoneInfo) {
 				t.dnsDone = time.Now()
 			},
-			GetConn: func(_ string) {
-				t.getConn = time.Now()
-				if t.dnsStart.IsZero() {
-					t.dnsStart = t.getConn
-				}
+			ConnectStart: func(_, _ string) {
 				if t.dnsDone.IsZero() {
-					t.dnsDone = t.getConn
+					t.dnsDone = time.Now()
 				}
+				if t.dnsStart.IsZero() {
+					t.dnsStart = t.dnsDone
+				}
+			},
+			ConnectDone: func(net, addr string, err error) {
+				t.connectDone = time.Now()
+			},
+			GetConn: func(_ string) {
+				t.getConn = time.Now()
 			},
 			GotConn: func(ci httptrace.GotConnInfo) {
 				t.gotConn = time.Now()