ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 3));

    ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 3));

/**
 * A bounded {@linkplain BlockingQueue blocking queue} backed by an array. This queue orders
 * elements FIFO (first-in-first-out). The head of the queue is that element that has been
 * on the queue the longest time. The tail of the queue is that element that has been on
 * the queue the shortest time. New elements are inserted at the tail of the queue, and the queue
 * retrieval operations obtain elements at the head of the queue.

 * incoming messages. But it does not guarantee that the other peer will successfully receive all of
 * its incoming messages.
 *
 * ## Message Queue
 *
 * Messages enqueued with [send] are buffered in an outgoing message queue. This queue has a 16 MiB
 * limit. If a call to [send] would cause the queue to exceed this limit, the web socket will
 * initiate a graceful shutdown (close code 1001) and `send()` will return `false`. No exception is

/**
 * A bounded {@linkplain BlockingQueue blocking queue} backed by an array. This queue orders
 * elements FIFO (first-in-first-out). The head of the queue is that element that has been
 * on the queue the longest time. The tail of the queue is that element that has been on
 * the queue the shortest time. New elements are inserted at the tail of the queue, and the queue
 * retrieval operations obtain elements at the head of the queue.

 * defined as the <i>least</i> element in the queue according to the queue's comparator. But unlike
 * a regular priority queue, the methods {@link #peekLast}, {@link #pollLast} and {@link
 * #removeLast} are also provided, to act on the <i>greatest</i> element in the queue instead.
 *
 * <p>A min-max priority queue can be configured with a maximum size. If so, each time the size of

            : new DirectStarter();
  }

  /** The actual reference queue that our background thread will poll. */
  final ReferenceQueue<Object> queue;

  final PhantomReference<Object> frqRef;

  /** Whether or not the background thread started successfully. */
  final boolean threadStarted;

  /** Constructs a new queue. */
  public FinalizableReferenceQueue() {

 * defined as the <i>least</i> element in the queue according to the queue's comparator. But unlike
 * a regular priority queue, the methods {@link #peekLast}, {@link #pollLast} and {@link
 * #removeLast} are also provided, to act on the <i>greatest</i> element in the queue instead.
 *
 * <p>A min-max priority queue can be configured with a maximum size. If so, each time the size of

            : new DirectStarter();
  }

  /** The actual reference queue that our background thread will poll. */
  final ReferenceQueue<Object> queue;

  final PhantomReference<Object> frqRef;

  /** Whether or not the background thread started successfully. */
  final boolean threadStarted;

  /** Constructs a new queue. */
  public FinalizableReferenceQueue() {

      ReferenceQueue<Object> queue,
      PhantomReference<Object> frqReference) {
    this.queue = queue;

    this.finalizableReferenceClassReference = new WeakReference<>(finalizableReferenceClass);

    // Keep track of the FRQ that started us so we know when to stop.
    this.frqReference = frqReference;
  }

  /** Loops continuously, pulling references off the queue and cleaning them up. */