* {@link #previousElements} if the reverse is true, or -- overriding both of these -- {@code
     * null} if {@code remove()} or {@code add()} has been called more recently than either. We use
     * this to determine which stack to pop from on a call to {@code remove()} (or to pop from and
     * push to on a call to {@code set()}).
     */

          // Overriding this to work around the fact that InputStream's default implementation of
          // this method will silently swallow exceptions thrown by the single-byte read() method
          // (other than on the first call to it), which in this case can cause invalid encoded
          // strings to not throw an exception.
          // See https://github.com/google/guava/issues/3542

    @Override
    public @Nullable Object[] toArray() {
      synchronized (mutex) {
        /*
         * toArrayImpl returns `@Nullable Object[]` rather than `Object[]` but only because it can
         * be used with collections that may contain null. This collection never contains nulls, so
         * we could return `Object[]`. But this class is private and J2KT cannot change return types

   * IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
   * fromElement}. However, this method doesn't throw an exception in that situation, but instead
   * keeps the original {@code fromElement}. Similarly, this method keeps the original {@code
   * toElement}, instead of throwing an exception, if passed a {@code toElement} greater than an
   * earlier {@code toElement}.
   */
  @Override

   *
   * <p>If {@code expectedSize} is exactly the number of entries 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 entries added to the builder.
   *

   * instead.
   *
   * <p><b>Note:</b> If {@code elements} is a {@code SortedSet} with an explicit comparator, this
   * method has different behavior than {@link TreeSet#TreeSet(SortedSet)}, which returns a {@code
   * TreeSet} with that comparator.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,

   * operates per-segment rather than globally for increased implementation simplicity. We expect
   * the cache hit rate to be similar to that of a global LRU algorithm.
   */

  // Constants

  /**
   * The maximum capacity, used if a higher value is implicitly specified by either of the
   * constructors with arguments. MUST be a power of two no greater than {@code 1<<30} to ensure

      if (collection.size() <= 2L * k) {
        // In this case, just dumping the collection to an array and sorting is
        // faster than using the implementation for Iterator, which is
        // specialized for k much smaller than n.

        @SuppressWarnings("unchecked") // c only contains E's and doesn't escape
        E[] array = (E[]) collection.toArray();
        Arrays.sort(array, this);

    return new LinkedBlockingDeque<>();
  }

  /**
   * Creates an empty {@code LinkedBlockingDeque} with the given (fixed) capacity.
   *
   * @throws IllegalArgumentException if {@code capacity} is less than 1
   * @since 12.0
   */
  @J2ktIncompatible
  @GwtIncompatible // LinkedBlockingDeque
  public static <E> LinkedBlockingDeque<E> newLinkedBlockingDeque(int capacity) {
    return new LinkedBlockingDeque<>(capacity);

    return (Collector) ONLY_ELEMENT;
  }

  /**
   * This atrocity is here to let us report several of the elements in the stream if there were more
   * than one, not just two.
   */
  private static final class ToOptionalState {
    static final int MAX_EXTRAS = 4;

    @CheckForNull Object element;
    List<Object> extras;

    ToOptionalState() {