labelQueue.add(label);
    }

    /**
     * Dispatches all listeners {@linkplain #enqueue enqueued} prior to this call, serially and in
     * order.
     */
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    void dispatch() {
      boolean scheduleEventRunner = false;
      synchronized (this) {
        if (!isThreadScheduled) {
          isThreadScheduled = true;

      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit) throws ExecutionException {
    return callWithTimeout(callable, timeoutDuration, timeoutUnit);
  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void runWithTimeout(Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit) {
    checkNotNull(runnable);
    checkNotNull(timeoutUnit);
    try {
      runnable.run();

  @ParametricNullness private final V value;

  ImmediateFuture(@ParametricNullness V value) {
    this.value = value;
  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void addListener(Runnable listener, Executor executor) {
    checkNotNull(listener, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");
    try {

      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit) throws ExecutionException {
    return callWithTimeout(callable, timeoutDuration, timeoutUnit);
  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void runWithTimeout(Runnable runnable, long timeoutDuration, TimeUnit timeoutUnit) {
    checkNotNull(runnable);
    checkNotNull(timeoutUnit);
    try {
      runnable.run();

  }

  /**
   * Submits the given runnable to the given {@link Executor} catching and logging all {@linkplain
   * RuntimeException runtime exceptions} thrown by the executor.
   */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private static void executeListener(Runnable runnable, Executor executor) {
    try {
      executor.execute(runnable);
    } catch (Exception e) { // sneaky checked exception

  }

  /**
   * Submits the given runnable to the given {@link Executor} catching and logging all {@linkplain
   * RuntimeException runtime exceptions} thrown by the executor.
   */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private static void executeListener(Runnable runnable, Executor executor) {
    try {
      executor.execute(runnable);
    } catch (Exception e) { // sneaky checked exception