*
   * <p>This always holds: {@code 0 <= permitsToTake <= storedPermits}
   */
  abstract long storedPermitsToWaitTime(double storedPermits, double permitsToTake);

  /**
   * Returns the number of microseconds during cool down that we have to wait to get a new permit.
   */
  abstract double coolDownIntervalMicros();

  /** Updates {@code storedPermits} and {@code nextFreeTicketMicros} based on the current time. */

// binary format. The first words are a header with the following data:
//
//	1st word -- 0
//	2nd word -- 3
//	3rd word -- 0 if a c++ application, 1 if a java application.
//	4th word -- Sampling period (in microseconds).
//	5th word -- Padding.
func parseCPU(b []byte) (*Profile, error) {
	var parse func([]byte) (uint64, []byte)
	var n1, n2, n3, n4, n5 uint64
	for _, parse = range cpuInts {
		var tmp []byte

	name := t.Name()

	t.Run("runtime.lock", func(t *testing.T) {
		mus := make([]runtime.Mutex, 200)
		var needContention atomic.Int64
		delay := 100 * time.Microsecond // large relative to system noise, for comparison between clocks
		delayMicros := delay.Microseconds()

		// The goroutine that acquires the lock will only proceed when it
		// detects that its partner is contended for the lock. That will lead to

//
//	2009/01/23 01:23:23 message
//
// while flags Ldate | Ltime | Lmicroseconds | Llongfile produce,
//
//	2009/01/23 01:23:23.123123 /a/b/c/d.go:23: message
const (
	Ldate         = 1 << iota     // the date in the local time zone: 2009/01/23
	Ltime                         // the time in the local time zone: 01:23:23
	Lmicroseconds                 // microsecond resolution: 01:23:23.123123.  assumes Ltime.

		50 * time.Nanosecond,
		100 * time.Nanosecond,
		200 * time.Nanosecond,
		500 * time.Nanosecond,
		750 * time.Nanosecond,
		1 * time.Microsecond,
		5 * time.Microsecond,
		25 * time.Microsecond,
		250 * time.Microsecond,
		500 * time.Microsecond,
		1 * time.Millisecond,
		5 * time.Millisecond,
		100 * time.Millisecond,
		250 * time.Millisecond,
		500 * time.Millisecond,
		1 * time.Second,

		b.Skip("skipping: GOMAXPROCS=1")
	}

	wakeDelay := 5 * time.Microsecond
	for _, delay := range []time.Duration{
		0,
		1 * time.Microsecond,
		2 * time.Microsecond,
		5 * time.Microsecond,
		10 * time.Microsecond,
		20 * time.Microsecond,
		50 * time.Microsecond,
		100 * time.Microsecond,
	} {
		b.Run(delay.String(), func(b *testing.B) {
			if b.N == 0 {
				return
			}

		50 * time.Nanosecond,
		100 * time.Nanosecond,
		200 * time.Nanosecond,
		500 * time.Nanosecond,
		750 * time.Nanosecond,
		1 * time.Microsecond,
		5 * time.Microsecond,
		25 * time.Microsecond,
		250 * time.Microsecond,
		500 * time.Microsecond,
		1 * time.Millisecond,
		5 * time.Millisecond,
		100 * time.Millisecond,
		250 * time.Millisecond,
		500 * time.Millisecond,
		1 * time.Second,

			t.Errorf("unexpected error: %v", err)
		}
	}()

	for !fakeClock.HasWaiters() {
		time.Sleep(time.Microsecond)
	}

	fakeClock.Step(time.Second - time.Millisecond)
	if attempt != 0 {
		t.Fatalf("should still be waiting for condition")
	}
	fakeClock.Step(2 * time.Millisecond)

	select {
	case <-doneCh:

func TestMicroTimeUnmarshalJSONAndProtoEqual(t *testing.T) {
	cases := []struct {
		name   string
		input  MicroTime
		result bool
	}{
		{"nanosecond level precision", UnixMicro(123, 123123123), true},
		{"microsecond level precision", UnixMicro(123, 123123000), true},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			jsonData, err := c.input.MarshalJSON()
			if err != nil {

		f := ConditionFunc(func() (bool, error) {
			ch <- struct{}{}
			select {
			case <-done:
				return true, nil
			default:
			}
			return false, nil
		})

		if err := PollInfinite(time.Microsecond, f); err != nil {
			errc <- fmt.Errorf("unexpected error %v", err)
		}

		close(ch)
		complete <- struct{}{}
	}()

	// ensure the condition is opened
	<-ch