/** Uses an {@link ArrayList} to store value collections. */
    public ListMultimapBuilder<K0, @Nullable Object> arrayListValues() {
      return arrayListValues(DEFAULT_EXPECTED_VALUES_PER_KEY);
    }

    /**
     * Uses an {@link ArrayList} to store value collections, initialized to expect the specified
     * number of values per key.
     *

        flatteningToMultimap(
            input -> checkNotNull(keyFunction.apply(input)),
            input -> valuesFunction.apply(input).peek(Preconditions::checkNotNull),
            MultimapBuilder.linkedHashKeys().arrayListValues()::<K, V>build),
        ImmutableListMultimap::copyOf);
  }

  static <T extends @Nullable Object, K, V>
      Collector<T, ?, ImmutableSetMultimap<K, V>> toImmutableSetMultimap(