WriteStartup can use finishWrite().

finishWrite will only compress the frame body if the compress
flag is set in the outgoing write buffer. As this flag is explicitly
switched off in the writeHeader call it will never be compressed.

frame.go

@@ -353,13 +353,10 @@ func (f *framer) readFrame(head *frameHeader) error {
 		}
 	}
 
-	head.framer = f
 	f.header = head
 	return nil
 }
 
-// after a call to parseFrame the frame owns f.buf, and the framer
-// is safe to use its buffer again (it is fresh)
 func (f *framer) parseFrame() (frame, error) {
 	if f.header.version.request() {
 		return nil, NewErrProtocol("got a request frame from server: %v", f.header.version)
@@ -374,7 +371,7 @@ func (f *framer) parseFrame() (frame, error) {
 		err   error
 	)
 
-	// asumes that the frame body has been read into buf
+	// asumes that the frame body has been read into rbuf
 	switch f.header.op {
 	case opError:
 		frame = f.parseErrorFrame()
@@ -519,7 +516,6 @@ func (f *framer) finishWrite() error {
 	f.setLength(length)
 
 	_, err := f.w.Write(f.wbuf)
-	f.wbuf = f.wbuf[:0]
 	if err != nil {
 		return err
 	}
@@ -566,21 +562,10 @@ func (w *writeStartupFrame) writeFrame(framer *framer, streamID int) error {
 }
 
 func (f *framer) writeStartupFrame(streamID int, options map[string]string) error {
-	// startup frame must not have the compress flag set
 	f.writeHeader(f.flags&^flagCompress, opStartup, streamID)
 	f.writeStringMap(options)
-	f.setLength(len(f.wbuf) - f.headSize)
 
-	// dont use finishWrite here as it will use compression
-	// TODO: have a type which has a writeHeader / writeBody so we can do
-	// transparent compression
-	_, err := f.w.Write(f.wbuf)
-	f.wbuf = f.wbuf[:0]
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return f.finishWrite()
 }
 
 type writePrepareFrame struct {