@Keep
      public DummyScheduledThreadPoolExecutor() {
        super(1);
      }
    }

    @Keep
    public static final class DummyCountDownLatch extends CountDownLatch {
      @Keep
      public DummyCountDownLatch() {
        super(0);
      }
    }

    @Keep
    public static final class DummyRunnable implements Runnable, Serializable {
      @Override