public void testEnqueueAndDispatch_multithreaded() throws InterruptedException {
    Object listener = new Object();
    ExecutorService service = Executors.newFixedThreadPool(4);
    ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    try {
      queue.addListener(listener, service);

      final CountDownLatch latch = new CountDownLatch(1);
      Multiset<Object> counters = ConcurrentHashMultiset.create();

  public void testEnqueueAndDispatch_multithreaded() throws InterruptedException {
    Object listener = new Object();
    ExecutorService service = Executors.newFixedThreadPool(4);
    ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    try {
      queue.addListener(listener, service);

      final CountDownLatch latch = new CountDownLatch(1);
      Multiset<Object> counters = ConcurrentHashMultiset.create();