* compare as equal, A will be returned before B if iterator 1 was passed before iterator 2.
   *
   * @since 11.0
   */
  public static <T extends @Nullable Object> UnmodifiableIterator<T> mergeSorted(
      Iterable<? extends Iterator<? extends T>> iterators, Comparator<? super T> comparator) {
    checkNotNull(iterators, "iterators");
    checkNotNull(comparator, "comparator");

   * compare as equal, A will be returned before B if iterator 1 was passed before iterator 2.
   *
   * @since 11.0
   */
  public static <T extends @Nullable Object> UnmodifiableIterator<T> mergeSorted(
      Iterable<? extends Iterator<? extends T>> iterators, Comparator<? super T> comparator) {
    checkNotNull(iterators, "iterators");
    checkNotNull(comparator, "comparator");

    // When elements compare as equal (both C's have same letter), our merge should always return C1
    // before C2, since C1 is from the first iterator.

    Iterator<TestDatum> merged =
        Iterators.mergeSorted(ImmutableList.of(left.iterator(), right.iterator()), comparator);

    ImmutableList<TestDatum> result = ImmutableList.copyOf(merged);

    assertThat(result)
        .containsExactly(

    // When elements compare as equal (both C's have same letter), our merge should always return C1
    // before C2, since C1 is from the first iterator.

    Iterator<TestDatum> merged =
        Iterators.mergeSorted(ImmutableList.of(left.iterator(), right.iterator()), comparator);

    ImmutableList<TestDatum> result = ImmutableList.copyOf(merged);

    assertThat(result)
        .containsExactly(