// shutting down, so give it some time.
		time.Sleep(1 * time.Millisecond)
	}
	t.Errorf("Test appears to have leaked %s:\n%s", bad, stacks)
}

// waitCondition waits for fn to return true,
// checking immediately and then at exponentially increasing intervals.
func waitCondition(t testing.TB, delay time.Duration, fn func(time.Duration) bool) {
	t.Helper()
	start := time.Now()
	var since time.Duration
	for !fn(since) {