* not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to

    assertEquals(1, (int) mmHeap.peek());
    assertEquals(1, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(2, (int) mmHeap.peek());
    assertEquals(2, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(3, (int) mmHeap.peek());
    assertEquals(3, (int) mmHeap.poll());
    assertNull(mmHeap.peekLast());
    assertNull(mmHeap.peek());

  }

  private static <K, V> void assertNotificationEnqueued(
      LocalCache<K, V> map, K key, V value, int hash) {
    RemovalNotification<K, V> notification = map.removalNotificationQueue.poll();
    assertSame(key, notification.getKey());
    assertSame(value, notification.getValue());
  }

  // Segment eviction tests

  public void testDrainRecencyQueueOnWrite() {

  }

  private static <K, V> void assertNotificationEnqueued(
      LocalCache<K, V> map, K key, V value, int hash) {
    RemovalNotification<K, V> notification = map.removalNotificationQueue.poll();
    assertSame(key, notification.getKey());
    assertSame(value, notification.getValue());
  }

  // Segment eviction tests

  public void testDrainRecencyQueueOnWrite() {

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to

    public E peek() {
      synchronized (mutex) {
        return delegate().peek();
      }
    }

    @Override
    @CheckForNull
    public E poll() {
      synchronized (mutex) {
        return delegate().poll();
      }
    }

    @Override
    public E remove() {
      synchronized (mutex) {
        return delegate().remove();
      }
    }

      while (true) {
        Future<T> f = futureQueue.poll();
        if (f == null) {
          if (ntasks > 0) {
            --ntasks;
            futures.add(submitAndAddQueueListener(executorService, it.next(), futureQueue));
            ++active;
          } else if (active == 0) {
            break;
          } else if (timed) {
            f = futureQueue.poll(timeoutNanos, TimeUnit.NANOSECONDS);

    while (added < numElements) {
      // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
      // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
      added += q.drainTo(buffer, numElements - added);
      if (added < numElements) { // not enough elements immediately available; will have to poll
        E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);

      }
    }

    @GuardedBy("this")
    void drainKeyReferenceQueue(ReferenceQueue<K> keyReferenceQueue) {
      Reference<? extends K> ref;
      int i = 0;
      while ((ref = keyReferenceQueue.poll()) != null) {
        @SuppressWarnings("unchecked")
        E entry = (E) ref;
        map.reclaimKey(entry);
        if (++i == DRAIN_MAX) {
          break;
        }
      }
    }

    assertEquals(1, (int) mmHeap.peek());
    assertEquals(1, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(2, (int) mmHeap.peek());
    assertEquals(2, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(3, (int) mmHeap.peek());
    assertEquals(3, (int) mmHeap.poll());
    assertNull(mmHeap.peekLast());
    assertNull(mmHeap.peek());