private ScheduledFuture<@Nullable Void> submitToExecutor(Schedule schedule) {
        return executor.schedule(this, schedule.delay, schedule.unit);
      }
    }

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

  }

  @Override
  public final ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    return delegate.schedule(wrapTask(command), delay, unit);
  }

  @Override
  public final <V extends @Nullable Object> ScheduledFuture<V> schedule(
      Callable<V> task, long delay, TimeUnit unit) {
    return delegate.schedule(wrapTask(task), delay, unit);
  }

  @Override

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");
    return schedule(java.util.concurrent.Executors.callable(command), delay, unit);
  }

  @Override
  public <V> ListenableScheduledFuture<V> schedule(

    assertEquals(UNIT, unit);
    assertEquals(testRunnable, command);
  }

  public void testFixedRateSchedule() {
    Scheduler schedule = Scheduler.newFixedRateSchedule(INITIAL_DELAY, DELAY, UNIT);
    Cancellable unused =
        schedule.schedule(
            null,
            new ScheduledThreadPoolExecutor(1) {
              @Override
              public ScheduledFuture<?> scheduleAtFixedRate(

    return new NoOpScheduledExecutorService();
  }

  /**
   * Creates a scheduled executor service that runs each task in the thread that invokes {@code
   * execute/submit/schedule}, as in {@link CallerRunsPolicy}. This applies both to individually
   * submitted tasks and to collections of tasks submitted via {@code invokeAll}, {@code invokeAny},
   * {@code schedule}, {@code scheduleAtFixedRate}, and {@code scheduleWithFixedDelay}. In the case

    Future<?> possiblyIgnoredError = testExecutor.schedule(DO_NOTHING, 10, TimeUnit.MINUTES);
    mock.assertLastMethodCalled("scheduleRunnable", 10, TimeUnit.MINUTES);

    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError1 =
        testExecutor.schedule(Executors.callable(DO_NOTHING), 5, TimeUnit.SECONDS);

   * addListener/SES.schedule. The later racy write in cancel() is not guaranteed to be observed,
   * however that is fine since the correctness is based on the atomic state in our base class. The
   * initial write to timer is never definitely visible to Fire.run since it is assigned after
   * SES.schedule is called. Therefore Fire.run has to check for null. However, it should be visible

    assertEquals(UNIT, unit);
    assertEquals(testRunnable, command);
  }

  public void testFixedRateSchedule() {
    Scheduler schedule = Scheduler.newFixedRateSchedule(INITIAL_DELAY, DELAY, UNIT);
    Cancellable unused =
        schedule.schedule(
            null,
            new ScheduledThreadPoolExecutor(1) {
              @Override
              public ScheduledFuture<?> scheduleAtFixedRate(

  @Override
  public ListenableScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    Preconditions.checkNotNull(command, "command must not be null");
    Preconditions.checkNotNull(unit, "unit must not be null!");
    return schedule(java.util.concurrent.Executors.callable(command), delay, unit);
  }

  @Override
  public <V> ListenableScheduledFuture<V> schedule(

        .build();

    final long startNanos = System.nanoTime();
    final Call call = client.newCall(request);

    // Schedule a job to cancel the call in 1 second.
    executor.schedule(() -> {
      System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);
      call.cancel();