if r != rZero {
				pool.Put(r)
			}
		}
}

// NewSingleHandler creates a typed handler that can provide Marshal/Unmarshal.
// Use Register to register a server handler.
// Use Call to initiate a clientside call.
func NewSingleHandler[Req, Resp RoundTripper](h HandlerID, newReq func() Req, newResp func() Resp) *SingleHandler[Req, Resp] {
	s := SingleHandler[Req, Resp]{id: h}
	s.newReq, s.recycleReq = recycleFunc[Req](newReq)

}

// writeMessage writes a message to w without allocations.
func (ww *wsWriter) writeMessage(w io.Writer, s ws.State, op ws.OpCode, p []byte) error {
	const fin = true
	var frame ws.Frame
	if s.ClientSide() {
		// We do not need to copy the payload, since we own it.
		payload := p

		frame = ws.NewFrame(op, fin, payload)
		frame = ws.MaskFrameInPlace(frame)
	} else {
		frame = ws.NewFrame(op, fin, p)