delegate.forEach(action);
  }

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

  @Override
  public boolean contains(@CheckForNull Object object) {
    return delegate.contains(object);
  }

  @Override
  public boolean containsAll(Collection<?> collection) {
    if (collection instanceof ImmutableEnumSet<?>) {

      assertTrue(Thread.holdsLock(mutex));
      return delegate.columnMap();
    }

    @Override
    public boolean contains(Object rowKey, Object columnKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.contains(rowKey, columnKey);
    }

    @Override
    public boolean containsColumn(Object columnKey) {
      assertTrue(Thread.holdsLock(mutex));

    @Override
    public void clear() {
      synchronized (mutex) {
        delegate().clear();
      }
    }

    @Override
    public boolean contains(@CheckForNull Object o) {
      synchronized (mutex) {
        return delegate().contains(o);
      }
    }

    @Override
    public boolean containsAll(Collection<?> c) {
      synchronized (mutex) {
        return delegate().containsAll(c);

      for (int i = 0; i < startIndex; i++) {
        previousElements.push(nextElements.pop());
      }
    }

    @Override
    public void add(E e) {
      if (!features.contains(IteratorFeature.SUPPORTS_ADD)) {
        throw PermittedMetaException.UOE;
      }

      previousElements.push(e);
      stackWithLastReturnedElementAtTop = null;
    }

    @Override

        .containsExactly(Maps.immutableEntry(4, "d"), Maps.immutableEntry(2, "b"))
        .inOrder();
    assertThat(diff1.entriesOnlyOnRight().entrySet()).contains(Maps.immutableEntry(6, "z"));
    assertThat(diff1.entriesInCommon().entrySet()).contains(Maps.immutableEntry(1, "a"));
    assertThat(diff1.entriesDiffering().entrySet())
        .containsExactly(
            Maps.immutableEntry(5, ValueDifferenceImpl.create("e", "g")),

        .containsExactly(Maps.immutableEntry(4, "d"), Maps.immutableEntry(2, "b"))
        .inOrder();
    assertThat(diff1.entriesOnlyOnRight().entrySet()).contains(Maps.immutableEntry(6, "z"));
    assertThat(diff1.entriesInCommon().entrySet()).contains(Maps.immutableEntry(1, "a"));
    assertThat(diff1.entriesDiffering().entrySet())
        .containsExactly(
            Maps.immutableEntry(5, ValueDifferenceImpl.create("e", "g")),

  /**
   * Returns a {@code Collector} that accumulates the input elements into a new {@code
   * ImmutableSet}. Elements appear in the resulting set in the encounter order of the stream; if
   * the stream contains duplicates (according to {@link Object#equals(Object)}), only the first
   * duplicate in encounter order will appear in the result.
   *
   * @since 21.0
   */

      } else {
        break;
      }
      iterations++;
      if (iterations >= maxIterations) {
        @SuppressWarnings("nullness") // safe because we pass sort() a range that contains real Ts
        T[] castBuffer = (T[]) buffer;
        // We've already taken O(k log k), let's make sure we don't take longer than O(k log k).
        Arrays.sort(castBuffer, left, right + 1, comparator);
        break;

            KeyPresentBehavior.ANY_PRESENT,
            KeyAbsentBehavior.NEXT_LOWER);
    if (index == -1) {
      return null;
    } else {
      Range<K> range = ranges.get(index);
      return range.contains(key) ? values.get(index) : null;
    }
  }

  @Override
  @CheckForNull
  public Entry<Range<K>, V> getEntry(K key) {
    int index =
        SortedLists.binarySearch(
            ranges,

      table.put("cat", null, cellValue('d'));
      fail();
    } catch (NullPointerException expected) {
    }
    if (supportsNullValues()) {
      assertNull(table.put("cat", 2, null));
      assertTrue(table.contains("cat", 2));
    } else {
      try {
        table.put("cat", 2, null);
        fail();
      } catch (NullPointerException expected) {
      }
    }
    assertSize(3);
  }