code: public final static <T> Stream<Character> flatMapCharSequence(final Stream<T> stream, final Function<? super T, CharSequence> fn) {
          return stream.flatMap(fn.andThen(CharSequence::chars)
                                  .andThen(s->s.mapToObj(i->Character.toChars(i)[0])));
      }
docs: rename -flatMapCharSequence