@IgnoreJRERequirement // Users will use this only if they're already using Duration.
  public static ScheduledExecutorService getExitingScheduledExecutorService(
      ScheduledThreadPoolExecutor executor, Duration terminationTimeout) {
    return getExitingScheduledExecutorService(
        executor, toNanosSaturated(terminationTimeout), NANOSECONDS);
  }

  /**

    TestApplication application = new TestApplication();
    ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
    assertThat(application.getExitingScheduledExecutorService(executor)).isNotNull();
    assertTrue(executor.getThreadFactory().newThread(() -> {}).isDaemon());
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.

    TestApplication application = new TestApplication();
    ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
    assertThat(application.getExitingScheduledExecutorService(executor)).isNotNull();
    assertTrue(executor.getThreadFactory().newThread(() -> {}).isDaemon());
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.