*
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()

    Collector<String, ?, ImmutableListMultimap<Character, Character>> collector =
        ImmutableListMultimap.flatteningToImmutableListMultimap(
            str -> str.charAt(0), str -> Chars.asList(str.substring(1).toCharArray()).stream());
    BiPredicate<Multimap<?, ?>, Multimap<?, ?>> equivalence =
        Equivalence.equals()

                        collectionImpl.apply(ImmutableList.of()), (str, i) -> str + ":" + i)
                    .spliterator())
        .expect(ImmutableList.of());
    SpliteratorTester.of(
            () ->
                Streams.mapWithIndex(
                        collectionImpl.apply(ImmutableList.of("a", "b", "c", "d", "e")),
                        (str, i) -> str + ":" + i)
                    .spliterator())

  public void testFlatteningToImmutableSetMultimap() {
    Collector<String, ?, ImmutableSetMultimap<Character, Character>> collector =
        ImmutableSetMultimap.flatteningToImmutableSetMultimap(
            str -> str.charAt(0), str -> Chars.asList(str.substring(1).toCharArray()).stream());
    BiPredicate<Multimap<?, ?>, Multimap<?, ?>> equivalence =
        Equivalence.equals()

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()

   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(
   *             toMultimap(
   *                  str -> str.charAt(0),
   *                  str -> str.substring(1),
   *                  MultimapBuilder.treeKeys().arrayListValues()::build));
   *
   * // is equivalent to
   *
   * static final ListMultimap<Character, String> FIRST_LETTER_MULTIMAP;

        Multimaps.transformValues(
            multimap,
            new Function<String, Integer>() {

              @Override
              public Integer apply(String str) {
                return str.length();
              }
            });
    Entry<String, String> entry = multimap.entries().iterator().next();
    entry.setValue("bbb");

  }

  public void testFlatteningToMultimap() {
    Collector<String, ?, ListMultimap<Character, Character>> collector =
        Multimaps.flatteningToMultimap(
            str -> str.charAt(0),
            str -> Chars.asList(str.substring(1).toCharArray()).stream(),
            MultimapBuilder.linkedHashKeys().arrayListValues()::build);
    BiPredicate<Multimap<?, ?>, Multimap<?, ?>> equivalence =
        Equivalence.equals()