code: func makeShutdownCh() <-chan struct{} {
  	resultCh := make(chan struct{})
  
  	signalCh := make(chan os.Signal, 4)
  	signal.Notify(signalCh, ignoreSignals...)
  	signal.Notify(signalCh, forwardSignals...)
  	go func() {
  		for {
  			<-signalCh
  			resultCh <- struct{}{}
  		}
  	}()
  
  	return resultCh
  }
docs: // makeShutdownCh creates an interrupt listener and returns a channel.
  // A message will be sent on the channel for every interrupt received.