@J2ktIncompatible
  @GwtIncompatible // TODO
  @IgnoreJRERequirement // Users will use this only if they're already using Duration.
  public static ExecutorService getExitingExecutorService(
      ThreadPoolExecutor executor, Duration terminationTimeout) {
    return getExitingExecutorService(executor, toNanosSaturated(terminationTimeout), NANOSECONDS);
  }

  /**

    TestApplication application = new TestApplication();
    ThreadPoolExecutor executor =
        new ThreadPoolExecutor(1, 2, 3, SECONDS, new ArrayBlockingQueue<Runnable>(1));
    assertThat(application.getExitingExecutorService(executor)).isNotNull();
    assertTrue(executor.getThreadFactory().newThread(() -> {}).isDaemon());
  }

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

    TestApplication application = new TestApplication();
    ThreadPoolExecutor executor =
        new ThreadPoolExecutor(1, 2, 3, SECONDS, new ArrayBlockingQueue<Runnable>(1));
    assertThat(application.getExitingExecutorService(executor)).isNotNull();
    assertTrue(executor.getThreadFactory().newThread(() -> {}).isDaemon());
  }

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