fix: sendWindowUpdate respects deadlines (#105)

session.go

@@ -243,7 +243,7 @@ GET_ID:
 	s.streamLock.Unlock()
 
 	// Send the window update to create
-	if err := stream.sendWindowUpdate(); err != nil {
+	if err := stream.sendWindowUpdate(ctx.Done()); err != nil {
 		defer span.Done()
 		select {
 		case <-s.synCh:
@@ -271,7 +271,7 @@ func (s *Session) AcceptStream() (*Stream, error) {
 	for {
 		select {
 		case stream := <-s.acceptCh:
-			if err := stream.sendWindowUpdate(); err != nil {
+			if err := stream.sendWindowUpdate(nil); err != nil {
 				// don't return accept errors.
 				s.logger.Printf("[WARN] error sending window update before accepting: %s", err)
 				continue

stream.go

@@ -120,7 +120,7 @@ START:
 	n, _ = s.recvBuf.Read(b)
 
 	// Send a window update potentially
-	err = s.sendWindowUpdate()
+	err = s.sendWindowUpdate(s.readDeadline.wait())
 	return n, err
 }
 
@@ -209,7 +209,7 @@ func (s *Stream) sendFlags() uint16 {
 
 // sendWindowUpdate potentially sends a window update enabling
 // further writes to take place. Must be invoked with the lock.
-func (s *Stream) sendWindowUpdate() error {
+func (s *Stream) sendWindowUpdate(deadline <-chan struct{}) error {
 	// Determine the flags if any
 	flags := s.sendFlags()
 
@@ -238,7 +238,7 @@ func (s *Stream) sendWindowUpdate() error {
 
 	s.epochStart = now
 	hdr := encode(typeWindowUpdate, flags, s.id, delta)
-	return s.session.sendMsg(hdr, nil, nil)
+	return s.session.sendMsg(hdr, nil, deadline)
 }
 
 // sendClose is used to send a FIN