@AfterEach fun tearDown() {
    backend.shutdown()
  }

  @Test fun test() {
    val t1 = System.nanoTime() / 1e6

    val delays = mutableListOf(TimeUnit.MILLISECONDS.toNanos(1000), -1L)
    queue.schedule("task", TimeUnit.MILLISECONDS.toNanos(750)) {
      log.put("runOnce delays.size=${delays.size}")
      return@schedule delays.removeAt(0)
    }

    assertThat(log.take()).isEqualTo("runOnce delays.size=2")

  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long time, TimeUnit timeUnit) {
    return advance(timeUnit.toNanos(time));
  }

  /** Advances the ticker value by {@code nanoseconds}. */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long nanoseconds) {

  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long time, TimeUnit timeUnit) {
    return advance(timeUnit.toNanos(time));
  }

  /** Advances the ticker value by {@code nanoseconds}. */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  @CanIgnoreReturnValue
  public FakeTicker advance(long nanoseconds) {

    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {
      return duration.isNegative() ? Long.MIN_VALUE : Long.MAX_VALUE;
    }
  }

  private Internal() {}

    }

    @Override
    public boolean equals(@Nullable Object o) {
      if (o instanceof DurationSpec) {
        DurationSpec that = (DurationSpec) o;
        return unit.toNanos(duration) == that.unit.toNanos(that.duration);
      }
      return false;
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this)
          .add("duration", duration)

    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {
      return duration.isNegative() ? Long.MIN_VALUE : Long.MAX_VALUE;
    }
  }

  private Internal() {}

    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {
      return duration.isNegative() ? Long.MIN_VALUE : Long.MAX_VALUE;
    }
  }

  private Internal() {}

    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {
      return duration.isNegative() ? Long.MIN_VALUE : Long.MAX_VALUE;
    }
  }

  private Internal() {}

    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {
      return duration.isNegative() ? Long.MIN_VALUE : Long.MAX_VALUE;
    }
  }

  private Internal() {}

    synchronized (lock) {
      return shutdown && runningTasks == 0;
    }
  }

  @Override
  public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
    long nanos = unit.toNanos(timeout);
    synchronized (lock) {
      while (true) {
        if (shutdown && runningTasks == 0) {
          return true;
        } else if (nanos <= 0) {
          return false;
        } else {