@Override
    public boolean removeAll(Collection<?> c) {
      return removeAllImpl(this, c);
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      return super.retainAll(checkNotNull(c)); // GWT compatibility
    }
  }

  /**
   * Returns an immutable set instance containing the given enum elements. Internally, the returned
   * set will be backed by an {@link EnumSet}.
   *

  }

  private static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap,
      @CheckForNull Comparator<? super V> valueComparator) {
    checkNotNull(multimap); // eager for GWT
    if (multimap.isEmpty() && valueComparator == null) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable

   * @throws NullPointerException if {@code elements} contains a null element
   */
  public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements) {
    checkNotNull(elements); // TODO(kevinb): is this here only for GWT?
    return (elements instanceof Collection)
        ? copyOf((Collection<? extends E>) elements)
        : copyOf(elements.iterator());
  }

  /**

   * @since 11.0
   */
  public static <E extends @Nullable Object> SortedMultiset<E> unmodifiableSortedMultiset(
      SortedMultiset<E> sortedMultiset) {
    // it's in its own file so it can be emulated for GWT
    return new UnmodifiableSortedMultiset<>(checkNotNull(sortedMultiset));
  }

  /**
   * Returns an immutable multiset entry with the specified element and count. The entry will be
   * serializable if {@code e} is.

  }

  @J2ktIncompatible // Arrays.asList(...).subList() doesn't implement RandomAccess in J2KT.
  @GwtIncompatible // Arrays.asList(...).subList() doesn't implement RandomAccess in GWT
  public void testPartitionRandomAccess() {
    Iterator<Integer> source = asList(1, 2, 3).iterator();
    Iterator<List<Integer>> partitions = Iterators.partition(source, 2);

      fail();
    } catch (NullPointerException expected) {
    }
    builder.put("foo", 2);
    assertMapEquals(builder.buildOrThrow(), "foo", 2);
  }

  // for GWT compatibility
  static class SimpleEntry<K, V> extends AbstractMapEntry<K, V> {
    public K key;
    public V value;

    SimpleEntry(K key, V value) {
      this.key = key;
      this.value = value;
    }

 */
@GwtIncompatible // hasn't been tested yet
@ElementTypesAreNonnullByDefault
public abstract class ImmutableSortedMultiset<E> extends ImmutableMultiset<E>
    implements SortedMultiset<E> {
  // TODO(lowasser): GWT compatibility

  /**
   * Returns a {@code Collector} that accumulates the input elements into a new {@code
   * ImmutableMultiset}. Elements are sorted by the specified comparator.
   *

        int count = 0;
        for (; count < size && iterator.hasNext(); count++) {
          array[count] = iterator.next();
        }
        for (int i = count; i < size; i++) {
          array[i] = null; // for GWT
        }

        List<@Nullable T> list = Collections.unmodifiableList(Arrays.asList(array));
        // TODO(b/192579700): Use a ternary once it no longer confuses our nullness checker.