}

  public void testCopyOf_iterator_ordering() {
    SortedSet<String> set = copyOf(asIterator("e", "a", "f", "b", "d", "c"));
    assertThat(set).containsExactly("a", "b", "c", "d", "e", "f").inOrder();
  }

  public void testCopyOf_iterator_ordering_dupes() {
    SortedSet<String> set = copyOf(asIterator("e", "a", "e", "f", "b", "b", "d", "a", "c"));

   * an {@code Iterable} is impossible. However, the contents can be <i>copied</i> into a collection
   * using {@link Collections#list}.
   *
   * <p><b>Java 9 users:</b> use {@code enumeration.asIterator()} instead, unless it is important to
   * return an {@code UnmodifiableIterator} instead of a plain {@code Iterator}.
   */
  public static <T extends @Nullable Object> UnmodifiableIterator<T> forEnumeration(