* {@code stream.map(function).collect(Collectors.toCollection(supplier))}.
   *
   * <p>To collect to an {@link ImmutableMultiset}, use {@link
   * ImmutableMultiset#toImmutableMultiset}.
   *
   * @since 22.0
   */
  public static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(

          public int add(String element, int occurrences) {
            addCalls.incrementAndGet();
            return super.add(element, occurrences);
          }
        };
    ImmutableMultiset<String> adds =
        new ImmutableMultiset.Builder<String>().addCopies("x", 10).build();
    multiset.addAll(adds);
    assertEquals(1, addCalls.get());
  }

  public void testRemoveUnsupported() {

                  @Override
                  protected Multiset<String> create(String[] elements) {
                    return new StandardImplForwardingMultiset<>(ImmutableMultiset.copyOf(elements));
                  }
                })
            .named("ForwardingMultiset[ImmutableMultiset] with standard implementations")
            .withFeatures(CollectionSize.ANY, CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

   */
  @Override
  public ImmutableMultiset<K> keys() {
    return (ImmutableMultiset<K>) super.keys();
  }

  @Override
  ImmutableMultiset<K> createKeys() {
    return new Keys();
  }

  @SuppressWarnings("serial") // Uses writeReplace, not default serialization
  @WeakOuter
  private final class Keys extends ImmutableMultiset<K> {
    @Override

          multiset2.add(elements[i], i + 1);
        }
        return difference(multiset1, multiset2);
      }
    };
  }

  private static final ImmutableMultiset<String> ELEMENTS_TO_FILTER_OUT =
      ImmutableMultiset.of("foobar", "bazfoo", "foobar", "foobar");

  private static final Predicate<String> PREDICATE = not(Predicates.in(ELEMENTS_TO_FILTER_OUT));

          multiset2.add(elements[i], i + 1);
        }
        return difference(multiset1, multiset2);
      }
    };
  }

  private static final ImmutableMultiset<String> ELEMENTS_TO_FILTER_OUT =
      ImmutableMultiset.of("foobar", "bazfoo", "foobar", "foobar");

  private static final Predicate<String> PREDICATE = not(Predicates.in(ELEMENTS_TO_FILTER_OUT));

    return ImmutableSortedSet.copyOf(comparator, (Iterable<@NonNull E>) getDelegate());
  }

  /**
   * Returns an {@code ImmutableMultiset} containing all of the elements from this fluent iterable.
   *
   * <p><b>{@code Stream} equivalent:</b> pass {@link ImmutableMultiset#toImmutableMultiset} to
   * {@code stream.collect()}.
   *
   * @throws NullPointerException if any element is null
   * @since 19.0
   */

    return ImmutableSortedSet.copyOf(comparator, (Iterable<@NonNull E>) getDelegate());
  }

  /**
   * Returns an {@code ImmutableMultiset} containing all of the elements from this fluent iterable.
   *
   * <p><b>{@code Stream} equivalent:</b> pass {@link ImmutableMultiset#toImmutableMultiset} to
   * {@code stream.collect()}.
   *
   * @throws NullPointerException if any element is null
   * @since 19.0
   */

        ImmutableSet<Integer> immutableSet,
        SortedSet<Number> sortedSet,
        ImmutableSortedSet<Number> immutableSortedSet,
        Multiset<String> multiset,
        ImmutableMultiset<Integer> immutableMultiset,
        Multimap<String, Integer> multimap,
        ImmutableMultimap<String, Integer> immutableMultimap,
        Table<String, Integer, Exception> table,

      Collector<Range<E>, ?, ImmutableRangeSet<E>> toImmutableRangeSet() {
    return (Collector) TO_IMMUTABLE_RANGE_SET;
  }

  // Multisets

  static <T extends @Nullable Object, E> Collector<T, ?, ImmutableMultiset<E>> toImmutableMultiset(
      Function<? super T, ? extends E> elementFunction, ToIntFunction<? super T> countFunction) {
    checkNotNull(elementFunction);
    checkNotNull(countFunction);
    return Collector.of(