* elements of each iterator in {@code inputs}. The input iterators are not polled until
   * necessary.
   *
   * <p>The returned iterator supports {@code remove()} when the corresponding input iterator
   * supports it. The methods of the returned iterator may throw {@code NullPointerException} if any
   * of the input iterators is null.
   */

  }

  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));
  }

  }

  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));
  }

        return set1.isEmpty() && set2.isEmpty();
      }

      @Override
      public UnmodifiableIterator<E> iterator() {
        return new AbstractIterator<E>() {
          final Iterator<? extends E> itr1 = set1.iterator();
          final Iterator<? extends E> itr2 = set2.iterator();

          @Override
          @CheckForNull
          protected E computeNext() {
            if (itr1.hasNext()) {

      }

      int oldCount = values.size();
      if (occurrences >= oldCount) {
        values.clear();
      } else {
        Iterator<V> iterator = values.iterator();
        for (int i = 0; i < occurrences; i++) {
          iterator.next();
          iterator.remove();
        }
      }
      return oldCount;
    }

    @Override
    public void clear() {
      multimap.clear();

 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are
 * reflected in that iterator. These iterators never throw {@link ConcurrentModificationException}.
 *

    @Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.removeAll(delegate().iterator(), c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.retainAll(delegate().iterator(), c);
      }
    }

    private static final long serialVersionUID = 0;
  }

    @Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.removeAll(delegate().iterator(), c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.retainAll(delegate().iterator(), c);
      }
    }

    private static final long serialVersionUID = 0;
  }

 * Cache} interfaces. The {@code asMap} view (and its collection views) have <i>weakly consistent
 * iterators</i>. This means that they are safe for concurrent use, but if other threads modify the
 * cache after the iterator is created, it is undefined which of these changes, if any, are
 * reflected in that iterator. These iterators never throw {@link ConcurrentModificationException}.
 *

  @ParameterizedTest
  @ArgumentsSource(FileSystemParamProvider::class)
  fun iterator(parameters: Pair<FileSystem, Boolean>) {
    setUp(parameters.first, parameters.second)
    set("a", "a1", "a2")
    set("b", "b1", "b2")
    set("c", "c1", "c2")
    val iterator = cache.snapshots()
    assertThat(iterator.hasNext()).isTrue()
    iterator.next().use {
      assertThat(it.key()).isEqualTo("a")