func (d *dynamicSleeper) Timer(ctx context.Context) func() {
	t := time.Now()
	return func() {
		doneAt := time.Now()
		d.Sleep(ctx, doneAt.Sub(t))
	}
}

// Sleep sleeps the specified time multiplied by the sleep factor.
// If the factor is updated the sleep will be done again with the new factor.
func (d *dynamicSleeper) Sleep(ctx context.Context, base time.Duration) {
	for {
		// Grab current values