extends FlatMapSpliteratorOfPrimitive<InElementT, Integer, IntConsumer, Spliterator.OfInt>
      implements Spliterator.OfInt {
    FlatMapSpliteratorOfInt(
        @CheckForNull Spliterator.OfInt prefix,
        Spliterator<InElementT> from,
        Function<? super InElementT, Spliterator.@Nullable OfInt> function,
        int characteristics,
        long estimatedSize) {

        ImmutableSet.of(() -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get())));
  }

  /**
   * @since 28.1
   */
  public static SpliteratorTester<Integer> ofInt(Supplier<Spliterator.OfInt> spliteratorSupplier) {
    return new SpliteratorTester<>(
        ImmutableSet.of(
            () -> new GeneralSpliteratorOfObject<>(spliteratorSupplier.get()),

                    7))
        .expect('a', 'b', 'c', 'd', 'e', 'f', 'g');
  }

  public void testFlatMapToInt_nullStream() {
    SpliteratorTester.ofInt(
            () ->
                CollectSpliterators.flatMapToInt(
                    Arrays.spliterator(new Integer[] {1, 0, 1, 2, 3}),
                    (Integer i) -> i == 0 ? null : IntStream.of(i).spliterator(),