fix getSysConn to work with TLS

connection.go

@@ -21,6 +21,7 @@
 package tchannel
 
 import (
+	"crypto/tls"
 	"errors"
 	"fmt"
 	"io"
@@ -971,7 +972,18 @@ func (c *Connection) getLastActivityWriteTime() time.Time {
 }
 
 func getSysConn(conn net.Conn, log Logger) syscall.RawConn {
-	connSyscall, ok := conn.(syscall.Conn)
+	var (
+		connSyscall syscall.Conn
+		ok          bool
+	)
+	switch v := conn.(type) {
+	case syscall.Conn:
+		connSyscall = v
+		ok = true
+	case *tls.Conn:
+		connSyscall, ok = v.NetConn().(syscall.Conn)
+	}
+
 	if !ok {
 		log.WithFields(LogField{"connectionType", fmt.Sprintf("%T", conn)}).
 			Error("Connection does not implement SyscallConn.")

connection_internal_test.go

@@ -23,6 +23,7 @@ package tchannel
 import (
 	"bytes"
 	"net"
+	"net/http/httptest"
 	"syscall"
 	"testing"
 
@@ -79,4 +80,20 @@ func TestGetSysConn(t *testing.T) {
 		require.NotNil(t, sysConn)
 		assert.Empty(t, loggerBuf.String(), "expected no logs on success")
 	})
+
+	t.Run("SyscallConn is successful with TLS", func(t *testing.T) {
+		loggerBuf := &bytes.Buffer{}
+		logger := NewLogger(loggerBuf)
+
+		server := httptest.NewTLSServer(nil)
+		defer server.Close()
+
+		conn, err := net.Dial("tcp", server.Listener.Addr().String())
+		require.NoError(t, err, "failed to dial")
+		defer conn.Close()
+
+		sysConn := getSysConn(conn, logger)
+		require.NotNil(t, sysConn)
+		assert.Empty(t, loggerBuf.String(), "expected no logs on success")
+	})
 }