t.Fatalf("%d ticks of %s too slow: took %s, expected %s", Count, Delta, d, target)
	}
}

func TestAfterStop(t *testing.T) {
	t.Run("impl=chan", func(t *testing.T) {
		testAfterStop(t, NewTimer)
	})
	t.Run("impl=func", func(t *testing.T) {
		testAfterStop(t, newTimerFunc)
	})
}

func testAfterStop(t *testing.T, newTimer func(Duration) *Timer) {
	// We want to test that we stop a timer before it runs.