*         .collect(
   *             flatteningToImmutableSetMultimap(
   *                  str -> str.charAt(0),
   *                  str -> str.substring(1).chars().mapToObj(c -> (char) c));
   *
   * // is equivalent to
   *
   * static final ImmutableSetMultimap<Character, Character> FIRST_LETTER_MULTIMAP =
   *     ImmutableSetMultimap.<Character, Character>builder()

        }
      }
      return chars.subSequence(0, l + 1);
    }

    @Override
    public boolean canDecode(CharSequence chars) {
      checkNotNull(chars);
      chars = trimTrailingPadding(chars);
      if (!alphabet.isValidPaddingStartPosition(chars.length())) {
        return false;
      }
      for (int i = 0; i < chars.length(); i++) {
        if (!alphabet.canDecode(chars.charAt(i))) {
          return false;

    StringBuilder builder = new StringBuilder("abc");
    List<Character> chars = Lists.charactersOf(builder);
    assertEquals(asList('a', 'b', 'c'), chars);
    builder.append("def");
    assertEquals(asList('a', 'b', 'c', 'd', 'e', 'f'), chars);
    builder.deleteCharAt(5);
    assertEquals(asList('a', 'b', 'c', 'd', 'e'), chars);
  }

  public void testNewArrayListEmpty() {

    StringBuilder builder = new StringBuilder("abc");
    List<Character> chars = Lists.charactersOf(builder);
    assertEquals(asList('a', 'b', 'c'), chars);
    builder.append("def");
    assertEquals(asList('a', 'b', 'c', 'd', 'e', 'f'), chars);
    builder.deleteCharAt(5);
    assertEquals(asList('a', 'b', 'c', 'd', 'e'), chars);
  }

  public void testNewArrayListEmpty() {

   *         .collect(
   *             flatteningToImmutableListMultimap(
   *                  str -> str.charAt(0),
   *                  str -> str.substring(1).chars().mapToObj(c -> (char) c));
   *
   * // is equivalent to
   *
   * static final ImmutableListMultimap<Character, Character> FIRST_LETTER_MULTIMAP =
   *     ImmutableListMultimap.<Character, Character>builder()

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