extends FlatMapSpliteratorOfPrimitive<InElementT, Long, LongConsumer, Spliterator.OfLong>
      implements Spliterator.OfLong {
    FlatMapSpliteratorOfLong(
        Spliterator.@Nullable OfLong prefix,
        Spliterator<InElementT> from,
        Function<? super InElementT, Spliterator.@Nullable OfLong> function,
        int characteristics,
        long estimatedSize) {

      extends FlatMapSpliteratorOfPrimitive<InElementT, Long, LongConsumer, Spliterator.OfLong>
      implements Spliterator.OfLong {
    FlatMapSpliteratorOfLong(
        Spliterator.@Nullable OfLong prefix,
        Spliterator<InElementT> from,
        Function<? super InElementT, Spliterator.@Nullable OfLong> function,
        int characteristics,
        long estimatedSize) {

                    Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    4))
        .expect(1, 1, 2, 3);
  }

  public void testFlatMapToLong_nullStream() {
    SpliteratorTester.ofLong(
            () ->
                CollectSpliterators.flatMapToLong(
                    Arrays.spliterator(new Long[] {1L, 0L, 1L, 2L, 3L}),
                    (Long i) -> i == 0L ? null : LongStream.of(i).spliterator(),

    long estimatedSize = 0L;
    ImmutableList.Builder<Spliterator.OfLong> splitrsBuilder =
        new ImmutableList.Builder<>(streams.length);
    for (LongStream stream : streams) {
      isParallel |= stream.isParallel();
      Spliterator.OfLong splitr = stream.spliterator();
      splitrsBuilder.add(splitr);
      characteristics &= splitr.characteristics();

                    Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    4))
        .expect(1, 1, 2, 3);
  }

  public void testFlatMapToLong_nullStream() {
    SpliteratorTester.ofLong(
            () ->
                CollectSpliterators.flatMapToLong(
                    Arrays.spliterator(new Long[] {1L, 0L, 1L, 2L, 3L}),
                    (Long i) -> i == 0L ? null : LongStream.of(i).spliterator(),

    /*
     * This is an override that is not directly visible to callers, so NewApi will catch calls to
     * Collection.spliterator() where necessary.
     */
    @IgnoreJRERequirement
    public Spliterator.OfLong spliterator() {
      return Spliterators.spliterator(array, start, end, 0);
    }

    @Override
    public boolean contains(@Nullable Object target) {
      // Overridden to prevent a ton of boxing