code: func (w *realTimeoutFactory) TimeoutCh() (<-chan time.Time, func() bool) {
  	if w.timeout == 0 {
  		return neverExitWatch, func() bool { return false }
  	}
  	t := time.NewTimer(w.timeout)
  	return t.C, t.Stop
  }
docs: // TimeoutCh returns a channel which will receive something when the watch times out,
  // and a cleanup function to call when this happens.