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;

    // If the task is already scheduled, take the earlier of the two times.
    val existingIndex = futureTasks.indexOf(task)
    if (existingIndex != -1) {
      if (task.nextExecuteNanoTime <= executeNanoTime) {
        taskRunner.logger.taskLog(task, this) { "already scheduled" }
        return false
      }
      futureTasks.removeAt(existingIndex) // Already scheduled later: reschedule below!
    }

      object : Task("task one") {
        val schedules = mutableListOf(200.µs)

        override fun runOnce(): Long {
          if (schedules.isNotEmpty()) {
            redQueue.schedule(this, schedules.removeAt(0)) // Add it at the end also.
          }
          log += "scheduledTasks=${redQueue.scheduledTasks}"
          return -1L
        }
      }
    redQueue.schedule(task, 100.µs)

    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(

    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(

  }

  @Test fun taskFailsWithUncheckedException() {
    queue.schedule("task", TimeUnit.MILLISECONDS.toNanos(100)) {
      log.put("failing task running")
      throw RuntimeException("boom!")
    }

    queue.schedule("task", TimeUnit.MILLISECONDS.toNanos(200)) {
      log.put("normal task running")
      return@schedule -1L
    }

    queue.idleLatch().await(500, TimeUnit.MILLISECONDS)

 * ----------
 *
 * Tasks control their recurrence schedule. The [runOnce] function returns -1L to signify that the
 * task should not be executed again. Otherwise it returns a delay until the next execution.
 *
 * A task has at most one next execution. If the same task instance is scheduled multiple times, the
 * earliest one wins. This applies to both executions scheduled with [TaskRunner.Queue.schedule] and
 * those implied by the returned execution delay.

  }

  @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

    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

                logger.debug("Updating scheduled jobs. time:{}", schedulerTime);
            }
            final long now = systemHelper.getCurrentTimeAsLong();
            scheduledJobService.getScheduledJobListAfter(schedulerTime).forEach(scheduledJob -> {
                if (logger.isDebugEnabled()) {
                    logger.debug("Updating job schedule:{}", scheduledJob.getName());
                }
                try {