assertEquals(-1, matcher.indexIn(s));
    assertEquals(-1, matcher.indexIn(s, 0));
    assertEquals(-1, matcher.indexIn(s, 1));
    assertEquals(-1, matcher.indexIn(s, s.length()));
    try {
      matcher.indexIn(s, s.length() + 1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
    try {
      matcher.indexIn(s, -1);
      fail();

   * #matches} for each character.
   *
   * @param sequence the character sequence to examine from the beginning
   * @return an index, or {@code -1} if no character matches
   */
  public int indexIn(CharSequence sequence) {
    return indexIn(sequence, 0);
  }

  /**
   * Returns the index of the first matching BMP character in a character sequence, starting from a

   * #matches} for each character.
   *
   * @param sequence the character sequence to examine from the beginning
   * @return an index, or {@code -1} if no character matches
   */
  public int indexIn(CharSequence sequence) {
    return indexIn(sequence, 0);
  }

  /**
   * Returns the index of the first matching BMP character in a character sequence, starting from a

    return new Splitter(
        (splitter, toSplit) ->
            new SplittingIterator(splitter, toSplit) {
              @Override
              int separatorStart(int start) {
                return separatorMatcher.indexIn(toSplit, start);
              }

              @Override
              int separatorEnd(int separatorPosition) {
                return separatorPosition + 1;
              }
            });
  }

    return new Splitter(
        (splitter, toSplit) ->
            new SplittingIterator(splitter, toSplit) {
              @Override
              int separatorStart(int start) {
                return separatorMatcher.indexIn(toSplit, start);
              }

              @Override
              int separatorEnd(int separatorPosition) {
                return separatorPosition + 1;
              }
            });
  }