private Dispatcher dispatcher;

  public void testPerThreadQueuedDispatcher() {
    dispatcher = Dispatcher.perThreadDispatchQueue();
    dispatcher.dispatch(1, integerSubscribers.iterator());

    assertThat(dispatchedSubscribers)
        .containsExactly(
            i1,
            i2,
            i3, // Integer subscribers are dispatched to first.
            s1,

    }

    @Override
    public SortedMultiset<E> descendingMultiset() {
      return new StandardDescendingMultiset() {

        @Override
        Iterator<Entry<E>> entryIterator() {
          return backingMultiset.descendingMultiset().entrySet().iterator();
        }
      };
    }

    @Override
    public NavigableSet<E> elementSet() {
      return new StandardElementSet();
    }

    @Override

   * queue's iterator:
   *
   * {@snippet :
   * Queue<E> queue = Queues.synchronizedQueue(MinMaxPriorityQueue.<E>create());
   * ...
   * queue.add(element);  // Needn't be in synchronized block
   * ...
   * synchronized (queue) {  // Must synchronize on queue!
   *   Iterator<E> i = queue.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {

    }
  }

  /** Overridden column iterator to return columns values in globally sorted order. */
  @Override
  Iterator<C> createColumnKeyIterator() {
    Comparator<? super C> comparator = columnComparator();

    Iterator<C> merged =
        mergeSorted(
            transform(backingMap.values(), (Map<C, V> input) -> input.keySet().iterator()),
            comparator);

      return original.size();
    }

    @Override
    public Collection<V> values() {
      return original.values();
    }

    @Override
    Iterator<Cell<C, R, V>> cellIterator() {
      return Iterators.transform(original.cellSet().iterator(), Tables::transposeCell);
    }
  }

  private static <
          R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

  }

  /**
   * Returns a sequential {@link Stream} of the remaining contents of {@code iterator}. Do not use
   * {@code iterator} directly after passing it to this method.
   */
  public static <T extends @Nullable Object> Stream<T> stream(Iterator<T> iterator) {
    return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, 0), false);
  }

  /**

    }

    void setValue(@ParametricNullness V value) {
      checkState(current != null);
      current.setValue(value);
    }
  }

  /** An {@code Iterator} over distinct keys in key head order. */
  private final class DistinctKeyIterator implements Iterator<K> {
    final Set<K> seenKeys = Sets.<K>newHashSetWithExpectedSize(keySet().size());
    @Nullable Node<K, V> next = head;
    @Nullable Node<K, V> current;

    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override
  public UnmodifiableIterator<V> iterator() {
    return new UnmodifiableIterator<V>() {
      final UnmodifiableIterator<Entry<K, V>> entryItr = map.entrySet().iterator();

      @Override
      public boolean hasNext() {
        return entryItr.hasNext();
      }

      @Override
      public V next() {

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {