Function<? super T, ? extends Stream<? extends V>> valuesFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valuesFunction);
    return collectingAndThen(
        flatteningToMultimap(
            input -> checkNotNull(keyFunction.apply(input)),
            input -> valuesFunction.apply(input).peek(Preconditions::checkNotNull),
            MultimapBuilder.linkedHashKeys().arrayListValues()::<K, V>build),

          Function<? super T, ? extends Stream<? extends V>> valuesFunction) {
    checkNotNull(keyFunction);
    checkNotNull(valuesFunction);
    return collectingAndThen(
        flatteningToMultimap(
            input -> checkNotNull(keyFunction.apply(input)),
            input -> valuesFunction.apply(input).peek(Preconditions::checkNotNull),
            MultimapBuilder.linkedHashKeys().arrayListValues()::<K, V>build),

  }

  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);

          M extends Multimap<K, V>>
      Collector<T, ?, M> flatteningToMultimap(
          java.util.function.Function<? super T, ? extends K> keyFunction,
          java.util.function.Function<? super T, ? extends Stream<? extends V>> valueFunction,
          java.util.function.Supplier<M> multimapSupplier) {
    return CollectCollectors.<T, K, V, M>flatteningToMultimap(
        keyFunction, valueFunction, multimapSupplier);
  }