public static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,
          ToIntFunction<? super T> countFunction,
          Supplier<M> multisetSupplier) {
    return CollectCollectors.toMultiset(elementFunction, countFunction, multisetSupplier);
  }

  /**

   */
  public static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,
          ToIntFunction<? super T> countFunction,
          Supplier<M> multisetSupplier) {
    return CollectCollectors.toMultiset(elementFunction, countFunction, multisetSupplier);
  }

  /**

        (Multiset<E> multiset) -> ImmutableMultiset.copyFromEntries(multiset.entrySet()));
  }

  static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,
          ToIntFunction<? super T> countFunction,
          Supplier<M> multisetSupplier) {
    checkNotNull(elementFunction);
    checkNotNull(countFunction);

   *
   * @throws NullPointerException if any element is null
   * @since 19.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final ImmutableMultiset<@NonNull E> toMultiset() {
    return ImmutableMultiset.copyOf((Iterable<@NonNull E>) getDelegate());
  }

  /**
   * Returns an immutable map whose keys are the distinct elements of this {@code FluentIterable}