if msg.Err != nil {
			err = fmt.Errorf("remove pong failed: %v", &msg.Err)
		}
		m.addResponse(Response{Err: err})
		return
	}
	atomic.StoreInt64(&m.LastPong, time.Now().UnixNano())
}

// addResponse will add a response to the response channel.
// This function will never block
func (m *muxClient) addResponse(r Response) (ok bool) {
	m.respMu.Lock()
	defer m.respMu.Unlock()
	if m.closed {
		return false