code: func (f *FakeClock) NewTimer(d time.Duration) Timer {
  	f.lock.Lock()
  	defer f.lock.Unlock()
  	stopTime := f.time.Add(d)
  	ch := make(chan time.Time, 1) // Don't block!
  	timer := &fakeTimer{
  		fakeClock: f,
  		waiter: fakeClockWaiter{
  			targetTime: stopTime,
  			destChan:   ch,
  		},
  	}
  	f.waiters = append(f.waiters, timer.waiter)
  	return timer
  }
docs: // Fake version of time.NewTimer(d).