* of the deque's iterators:
   *
   * <pre>{@code
   * Deque<E> deque = Queues.synchronizedDeque(Queues.<E>newArrayDeque());
   * ...
   * deque.add(element);  // Needn't be in synchronized block
   * ...
   * synchronized (deque) {  // Must synchronize on deque!
   *   Iterator<E> i = deque.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {

  public void testDescendingNavigation() {
    List<Entry<E>> ascending = new ArrayList<>();
    Iterators.addAll(ascending, sortedMultiset.entrySet().iterator());
    List<Entry<E>> descending = new ArrayList<>();
    Iterators.addAll(descending, sortedMultiset.descendingMultiset().entrySet().iterator());
    Collections.reverse(descending);
    assertEquals(ascending, descending);
  }

  public void testDescendingNavigation() {
    List<Entry<E>> ascending = new ArrayList<>();
    Iterators.addAll(ascending, sortedMultiset.entrySet().iterator());
    List<Entry<E>> descending = new ArrayList<>();
    Iterators.addAll(descending, sortedMultiset.descendingMultiset().entrySet().iterator());
    Collections.reverse(descending);
    assertEquals(ascending, descending);
  }

  }

  @Override
  Iterator<Entry<E>> entryIterator() {
    // AbstractIterator makes this fairly clean, but it doesn't support remove(). To support
    // remove(), we create an AbstractIterator, and then use ForwardingIterator to delegate to it.
    Iterator<Entry<E>> readOnlyIterator =
        new AbstractIterator<Entry<E>>() {
          private final Iterator<Map.Entry<E, AtomicInteger>> mapEntries =

          // All collections are immutable empty. So safe for any type parameter.
          .put(Iterator.class, ImmutableSet.of().iterator())
          .put(PeekingIterator.class, Iterators.peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())

    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override
          @CheckForNull
          protected T computeNext() {
            while (iterator.hasNext()) {

  Range<C> span();

  // Views

  /**
   * Returns a view of the {@linkplain Range#isConnected disconnected} ranges that make up this
   * range set. The returned set may be empty. The iterators returned by its {@link
   * Iterable#iterator} method return the ranges in increasing order of lower bound (equivalently,
   * of upper bound).
   */
  Set<Range<C>> asRanges();

  /**

          // All collections are immutable empty. So safe for any type parameter.
          .put(Iterator.class, ImmutableSet.of().iterator())
          .put(PeekingIterator.class, Iterators.peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())

      lastEntry = entry;
    }

    @Override
    public void setSuccessorInValueSet(ValueSetLink<K, V> entry) {
      firstEntry = entry;
    }

    @Override
    public Iterator<V> iterator() {
      return new Iterator<V>() {
        ValueSetLink<K, V> nextEntry = firstEntry;
        @CheckForNull ValueEntry<K, V> toRemove;
        int expectedModCount = modCount;

        private void checkForComodification() {

      lastEntry = entry;
    }

    @Override
    public void setSuccessorInValueSet(ValueSetLink<K, V> entry) {
      firstEntry = entry;
    }

    @Override
    public Iterator<V> iterator() {
      return new Iterator<V>() {
        ValueSetLink<K, V> nextEntry = firstEntry;
        @CheckForNull ValueEntry<K, V> toRemove;
        int expectedModCount = modCount;

        private void checkForComodification() {