public static class Chars extends SampleElements<Character> {
    public Chars() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super('b', 'a', 'c', 'd', 'e');
    }
  }

  public static class Enums extends SampleElements<AnEnum> {
    public Enums() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super(AnEnum.B, AnEnum.A, AnEnum.C, AnEnum.D, AnEnum.E);
    }
  }

  public static class Chars extends SampleElements<Character> {
    public Chars() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super('b', 'a', 'c', 'd', 'e');
    }
  }

  public static class Enums extends SampleElements<AnEnum> {
    public Enums() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super(AnEnum.B, AnEnum.A, AnEnum.C, AnEnum.D, AnEnum.E);
    }
  }

          SpliteratorDecompositionStrategy.ALL_STRATEGIES) {
        List<E> resultsForStrategy = new ArrayList<>();
        strategy.forEach(spliteratorSupplier.get(), resultsForStrategy::add);

        // TODO(cpovirk): better failure messages
        if ((characteristics & Spliterator.NONNULL) != 0) {
          assertFalse(resultsForStrategy.contains(null));
        }
        if ((characteristics & Spliterator.SORTED) != 0) {

  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method
   * exists only to hide {@link ImmutableMap#builder} from consumers of {@code ImmutableSortedMap}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedMap#naturalOrder}, which offers better type-safety.
   */
  @DoNotCall("Use naturalOrder")
  @Deprecated

  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  @Beta // TODO: b/288085449 - Remove.
  public static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
    throw new UnsupportedOperationException();
  }

  /**
   * Not supported. Use {@link #naturalOrder}, which offers better type-safety, instead. This method

   *     directly, or use a combination of {@link #throwIfUnchecked} and {@code throw new
   *     RuntimeException(e)}. But consider whether users would be better off if your API threw a
   *     different type of exception. For background on the deprecation, read <a
   *     href="https://goo.gl/Ivn2kc">Why we deprecated {@code Throwables.propagate}</a>.
   */
  @CanIgnoreReturnValue

   *     directly, or use a combination of {@link #throwIfUnchecked} and {@code throw new
   *     RuntimeException(e)}. But consider whether users would be better off if your API threw a
   *     different type of exception. For background on the deprecation, read <a
   *     href="https://goo.gl/Ivn2kc">Why we deprecated {@code Throwables.propagate}</a>.
   */
  @CanIgnoreReturnValue

    Builder<String, Integer> builder =
        ImmutableSortedMap.<String, Integer>naturalOrder()
            .put("one", 1)
            .put("one", 2); // throwing on this line would be even better

    try {
      builder.build();
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testOf() {

   *
   * <p>If {@code expectedSize} is exactly the number of elements added to the builder before {@link
   * Builder#build} is called, the builder is likely to perform better than an unsized {@link
   * #builder()} would have.
   *
   * <p>It is not specified if any performance benefits apply if {@code expectedSize} is close to,
   * but not exactly, the number of elements added to the builder.

        // condition efficiently without _introducing_ deadlock is probably
        // tricky. For now, just accept the race condition---missing a warning
        // now and then is still better than having no deadlock detection.
        allowedPriorLocks.put(acquiredLock, new ExampleStackTrace(acquiredLock, this));
      } else {
        // Unsafe acquisition order detected. Create and cache a