* `Function<@Nullable A, @Nullable B>` already had to find a workaround. Still, there is a *ton* of
 * fallout from trying to switch. I would be shocked if the switch would offer benefits to anywhere
 * near enough users to justify the costs.
 *
 * Fortunately, if anyone does want to use a Converter as a `Function<@Nullable A, @Nullable B>`,
 * it's easy to get one: `converter::convert`.
 *

    return (ReferenceEntry<K, V>) NullEntry.INSTANCE;
  }

  static final Queue<?> DISCARDING_QUEUE =
      new AbstractQueue<Object>() {
        @Override
        public boolean offer(Object o) {
          return true;
        }

        @CheckForNull
        @Override
        public Object peek() {
          return null;
        }

        @CheckForNull
        @Override

 *       actually do so, to avoid implying repeat-iterability.) {@code FluentIterable}, on the other
 *       hand, is multiple-use, and does implement {@link Iterable}.
 *   <li>Streams offer many features not found here, including {@code min/max}, {@code distinct},
 *       {@code reduce}, {@code sorted}, the very powerful {@code collect}, and built-in support for
 *       parallelizing stream operations.

    EvictingQueue<String> queue = EvictingQueue.create(0);
    assertEquals(0, queue.size());

    assertTrue(queue.add("hi"));
    assertEquals(0, queue.size());

    assertTrue(queue.offer("hi"));
    assertEquals(0, queue.size());

    assertFalse(queue.remove("hi"));
    assertEquals(0, queue.size());

    try {
      queue.element();
      fail();

  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
   * exists only to hide {@link ImmutableMap#builder} from consumers of {@code ImmutableSortedMap}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedMap#naturalOrder}, which offers better type-safety.
   */
  @DoNotCall("Use naturalOrder")
  @Deprecated

 *   <li>{@code java.util.Optional} has the additional methods {@code ifPresent}, {@code filter},
 *       {@code flatMap}, and {@code orElseThrow}.
 *   <li>{@code java.util} offers the primitive-specialized versions {@code OptionalInt}, {@code
 *       OptionalLong} and {@code OptionalDouble}, the use of which is recommended; Guava does not
 *       have these.
 * </ul>
 *

      checkNotNull(subscribers);
      // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
      Queue<Event> queueForThread = requireNonNull(queue.get());
      queueForThread.offer(new Event(event, subscribers));

      if (!dispatching.get()) {
        dispatching.set(true);
        try {
          Event nextEvent;
          while ((nextEvent = queueForThread.poll()) != null) {

    SortedMap<Integer, AtomicInteger> replica = Maps.newTreeMap();
    assertTrue("Empty heap should be OK", mmHeap.isIntact());
    for (int i = 0; i < heapSize; i++) {
      int randomInt = random.nextInt();
      mmHeap.offer(randomInt);
      insertIntoReplica(replica, randomInt);
    }
    assertIntact(mmHeap);
    assertEquals(heapSize, mmHeap.size());
    int currentHeapSize = heapSize;

  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
   * exists only to hide {@link ImmutableSet#builder} from consumers of {@code ImmutableSortedSet}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedSet#naturalOrder}, which offers better type-safety.
   */
  @DoNotCall("Use naturalOrder")
  @Deprecated

 * ImmutableListMultimap}, which have well-defined {@link #equals} semantics, thus avoiding a common
 * source of bugs and confusion.
 *
 * <p><b>Note:</b> every {@link ImmutableMultimap} offers an {@link #inverse} view, so there is no
 * need for a distinct {@code ImmutableBiMultimap} type.
 *
 * <p><a id="iteration"></a>
 *