code: func (r *Supervisor) CancelAll() {
  	var cancelled []delayedStart
  
  	r.mu.Lock()
  	for _, delay := range r.delays {
  		delay.cancel()
  	}
  	r.mu.Unlock()
  
  	for _, delay := range cancelled {
  		<-delay.doneCh
  	}
  }
docs: // CancelAll aborts all pending restarts and waits for any instances of
  // StartNow that have already triggered to complete.