Streams.forEachPair(
        Stream.of("a", "b", "c"), Stream.iterate(1, i -> i + 1), (a, b) -> list.add(a + ":" + b));
    assertThat(list).containsExactly("a:1", "b:2", "c:3");
  }

  public void testForEachPair_parallel() {
    Stream<String> streamA = IntStream.range(0, 100000).mapToObj(String::valueOf).parallel();
    Stream<Integer> streamB = IntStream.range(0, 100000).mapToObj(i -> i).parallel();