// Send async.
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()
		var ack message
		ack.Op = OpAckMux
		ack.Flags = m.BaseFlags
		ack.MuxID = m.ID
		m.send(ack)
		if debugPrint {
			fmt.Println("connected stream mux:", ack.MuxID)
		}
	}()

	// Data inbound to the handler
	var handlerIn chan []byte
	if inboundCap > 0 {
		m.inbound = make(chan []byte, inboundCap)

	Payload    []byte    // Optional payload.
}

// Flags is a set of flags set on a message.
type Flags uint8

func (m message) String() string {
	var res []string
	if m.MuxID != 0 {
		res = append(res, fmt.Sprintf("MuxID: %v", m.MuxID))
	}
	if m.Seq != 0 {
		res = append(res, fmt.Sprintf("Seq: %v", m.Seq))
	}
	if m.DeadlineMS != 0 {
		res = append(res, fmt.Sprintf("Deadline: %vms", m.DeadlineMS))
	}

	// If the request context is canceled, the stream will no longer process requests.
	// Requests sent cannot be used any further by the called.
	Requests chan<- []byte

	muxID uint64
	ctx   context.Context
}

// Send a payload to the remote server.
func (s *Stream) Send(b []byte) error {
	if s.Requests == nil {
		return errors.New("stream does not accept requests")
	}
	select {