r.retryFn()
		r.retryFn = nil
	}
}

func (r *receiver) reset() bool {
	r.lock.Lock()
	defer r.lock.Unlock()
	was := r.run
	r.run = false
	return was
}

func (r *receiver) setRetryFn(retryFn func()) {
	r.lock.Lock()
	defer r.lock.Unlock()
	r.retryFn = retryFn
}

// A single change event in the fake timer.
type timerUpdate struct {
	active bool
	next   time.Duration // iff active == true