* based on the first time it was added, again unless {@link #orderEntriesByValue} was called.
     *
     * <p>In the current implementation, all values associated with a given key are stored in the
     * {@code Builder} object, even though only one of them will be used in the built map. If there
     * can be many repeated keys, it may be more space-efficient to use a {@link

     * stack so that it is returned by the next call to {@link Iterator#next()}. If the element is
     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can

 * equivalent elements are added to it, it is undefined which will come first in the output.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class TopKSelector<
    T extends @Nullable Object> {

  /**
   * Returns a {@code TopKSelector} that collects the lowest {@code k} elements added to it,

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**
   * Returns an immutable set containing the given elements, minus duplicates, in the order each was

  public void testPowerSetIteration_manual() {
    ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3);
    Set<Set<Integer>> powerSet = powerSet(elements);
    // The API doesn't promise this iteration order, but it's convenient here.
    Iterator<Set<Integer>> i = powerSet.iterator();
    assertEquals(ImmutableSet.of(), i.next());
    assertEquals(ImmutableSet.of(1), i.next());
    assertEquals(ImmutableSet.of(2), i.next());

  @Retention(RetentionPolicy.RUNTIME)
  private @interface Generates {}

  /**
   * Annotates a method to generate the "empty" instance of a collection. This method should accept
   * no parameter. The value it generates should be unequal to the values generated by methods
   * annotated with {@link Generates}.
   */
  @Target(ElementType.METHOD)
  @Retention(RetentionPolicy.RUNTIME)
  private @interface Empty {}

        return false;
      }
    }

    @Override
    int indexOf(@CheckForNull Object target) {
      if (contains(target)) {
        @SuppressWarnings("unchecked") // if it's contained, it's definitely a C
        C c = (C) requireNonNull(target);
        long total = 0;
        for (Range<C> range : ranges) {
          if (range.contains(c)) {

        return false;
      }
    }

    @Override
    int indexOf(@CheckForNull Object target) {
      if (contains(target)) {
        @SuppressWarnings("unchecked") // if it's contained, it's definitely a C
        C c = (C) requireNonNull(target);
        long total = 0;
        for (Range<C> range : ranges) {
          if (range.contains(c)) {

      totalCount += count;
      return this;
    }

    AvlNode<E> add(
        Comparator<? super E> comparator, @ParametricNullness E e, int count, int[] result) {
      /*
       * It speeds things up considerably to unconditionally add count to totalCount here,
       * but that destroys failure atomicity in the case of count overflow. =(
       */
      int cmp = comparator.compare(e, getElement());

   * is complete. It does so by using daemon threads and adding a shutdown hook to wait for their
   * completion.
   *
   * <p>This is mainly for fixed thread pools. See {@link Executors#newFixedThreadPool(int)}.
   *
   * @param executor the executor to modify to make sure it exits when the application is finished