public final void clear() {
    backingMap.clear();
    size = 0;
  }

  /**
   * Skeleton of per-entry iterators. We could push this down and win a few bytes, but it's complex
   * enough it's not especially worth it.
   */
  abstract class Itr<T extends @Nullable Object> implements Iterator<T> {
    int entryIndex = backingMap.firstIndex();
    int toRemove = -1;
    int expectedModCount = backingMap.modCount;

                @Override
                public Iterator<Entry<String, String>> iterator() {
                  return new Iterator<Entry<String, String>>() {

                    final Iterator<Entry<String, String>> iterator = map.entrySet().iterator();

                    @Override
                    public void remove() {
                      iterator.remove();
                    }

      }

      @Override
      public Iterator<Entry<E>> iterator() {
        return entryIterator();
      }

      @Override
      public int size() {
        return forwardMultiset().entrySet().size();
      }
    }
    return new EntrySetImpl();
  }

  @Override
  public Iterator<E> iterator() {
    return Multisets.iteratorImpl(this);
  }

  @Override

    @Override
    Multiset<E> multiset() {
      return AbstractMultiset.this;
    }

    @Override
    public Iterator<E> iterator() {
      return elementIterator();
    }
  }

  abstract Iterator<E> elementIterator();

  @LazyInit @CheckForNull private transient Set<Entry<E>> entrySet;

  @Override
  public Set<Entry<E>> entrySet() {

  }

  public void testSize1() {
    Iterator<Integer> iterator = singleton(0).iterator();
    assertEquals(1, Iterators.size(iterator));
  }

  public void testSize_partiallyConsumed() {
    Iterator<Integer> iterator = asList(1, 2, 3, 4, 5).iterator();
    iterator.next();
    iterator.next();
    assertEquals(3, Iterators.size(iterator));
  }

    checkNotNull(iterable);
    Iterators.checkNonnegative(position);
    if (iterable instanceof List) {
      List<? extends T> list = Lists.cast(iterable);
      return (position < list.size()) ? list.get(position) : defaultValue;
    } else {
      Iterator<? extends T> iterator = iterable.iterator();
      Iterators.advance(iterator, position);
      return Iterators.getNext(iterator, defaultValue);
    }
  }

 * PeekingIterator}</a>.
 *
 * @author Mick Killianey
 * @since 2.0
 */
@DoNotMock("Use Iterators.peekingIterator")
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface PeekingIterator<E extends @Nullable Object> extends Iterator<E> {
  /**
   * Returns the next element in the iteration, without advancing the iteration.
   *

      this.multiset = multiset;
    }

    @Override
    final SortedMultiset<E> multiset() {
      return multiset;
    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.elementIterator(multiset().entrySet().iterator());
    }

    @Override
    public Comparator<? super E> comparator() {
      return multiset().comparator();
    }

    @Override

    Iterator<T> iteratorA = iterableA.iterator();
    Iterator<T> iteratorB = iterableB.iterator();

    while (iteratorA.hasNext() && iteratorB.hasNext()) {
      if (!elementEquivalence.equivalent(iteratorA.next(), iteratorB.next())) {
        return false;
      }
    }

    return !iteratorA.hasNext() && !iteratorB.hasNext();
  }

  @Override

    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));
      return delegate.iterator();
    }

    @Override
    public int size() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.size();
    }