SubscriberRegistry(EventBus bus) {
    this.bus = checkNotNull(bus);
  }

  /** Registers all subscriber methods on the given listener object. */
  void register(Object listener) {
    Multimap<Class<?>, Subscriber> listenerMethods = findAllSubscribers(listener);

    for (Entry<Class<?>, Collection<Subscriber>> entry : listenerMethods.asMap().entrySet()) {
      Class<?> eventType = entry.getKey();

    server.processNextFrame()
    client.listener.assertClosing(1000, "Hello!")
    server.listener.assertClosing(1000, "Hi!")
    client.webSocket!!.finishReader()
    server.webSocket!!.finishReader()
    client.listener.assertClosed(1000, "Hello!")
    server.listener.assertClosed(1000, "Hi!")
    taskFaker.runTasks()
    assertThat(client.closed).isTrue()

    CountingRemovalListener<Object, Object> listener = countingRemovalListener();
    LoadingCache<Object, Object> nullCache =
        CacheBuilder.newBuilder().maximumSize(0).removalListener(listener).build(identityLoader());
    assertEquals(0, nullCache.size());
    Object key = new Object();
    assertSame(key, nullCache.getUnchecked(key));
    assertEquals(1, listener.getCount());
    assertEquals(0, nullCache.size());

    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

    future.set(1);
    listener.assertRun();
  }

  public void testListenLaterFailed() {
    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

    CountingRemovalListener<Object, Object> listener = countingRemovalListener();
    LoadingCache<Object, Object> nullCache =
        CacheBuilder.newBuilder().maximumSize(0).removalListener(listener).build(identityLoader());
    assertEquals(0, nullCache.size());
    Object key = new Object();
    assertSame(key, nullCache.getUnchecked(key));
    assertEquals(1, listener.getCount());
    assertEquals(0, nullCache.size());

    }

    @Override
    public void registerListener(@Nonnull Listener listener) {
        listeners.add(nonNull(listener));
    }

    @Override
    public void unregisterListener(@Nonnull Listener listener) {
        listeners.remove(nonNull(listener));
    }

    @Nonnull
    @Override
    public Collection<Listener> getListeners() {
        return Collections.unmodifiableCollection(listeners);

      throw exception;
    }
  }

  private static class RecordingListener extends Listener {
    static RecordingListener record(Service service) {
      RecordingListener listener = new RecordingListener(service);
      service.addListener(listener, directExecutor());
      return listener;
    }

    final Service service;

    RecordingListener(Service service) {

    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

    future.set(1);
    listener.assertRun();
  }

  public void testListenLaterFailed() {
    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

       * lets all futures share the same listener.
       *
       * We store `localFutures` inside the listener because `this.futures` might be nulled out by
       * the time the listener runs for the final future -- at which point we need to check all
       * inputs for exceptions *if* we're collecting values. If we're not, then the listener doesn't
       * need access to the futures again, so we can just pass `null`.

    // In the process we made one successful connection attempt.
    assertThat(listener.recordedEventTypes().filter { it == "ConnectStart" }).hasSize(2)
    assertThat(listener.recordedEventTypes().filter { it == "ConnectFailed" }).hasSize(1)
    assertThat(listener.recordedEventTypes().filter { it == "ConnectEnd" }).hasSize(1)
  }

  @Test
  fun reachesIpv6WhenIpv4IsDown() {