private final transient Set<E> delegate;

  ForwardingImmutableSet(Set<E> delegate) {
    // TODO(cpovirk): are we over-wrapping?
    this.delegate = Collections.unmodifiableSet(delegate);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override

   *
   * <p>If {@code delegate} is an instance created by an earlier call to {@code memoize}, it is
   * returned directly.
   */
  public static <T extends @Nullable Object> Supplier<T> memoize(Supplier<T> delegate) {
    if (delegate instanceof NonSerializableMemoizingSupplier
        || delegate instanceof MemoizingSupplier) {
      return delegate;
    }
    return delegate instanceof Serializable

  @Override
  public int size() {
    Set<E> delegate = delegateOrNull();
    return (delegate != null) ? delegate.size() : size;
  }

  @Override
  public boolean isEmpty() {
    return size() == 0;
  }

  @Override
  public @Nullable Object[] toArray() {
    if (needsAllocArrays()) {
      return new Object[0];
    }
    Set<E> delegate = delegateOrNull();

  private InvalidatableSet(
      Set<E> delegate, Supplier<Boolean> validator, Supplier<String> errorMessage) {
    this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {

  private final ListenableFuture<V> delegate;

  ForwardingFluentFuture(ListenableFuture<V> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  public void addListener(Runnable listener, Executor executor) {
    delegate.addListener(listener, executor);
  }

  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    return delegate.cancel(mayInterruptIfRunning);
  }

    implements SortedMultiset<E> {
  UnmodifiableSortedMultiset(SortedMultiset<E> delegate) {
    super(delegate);
  }

  @Override
  protected SortedMultiset<E> delegate() {
    return (SortedMultiset<E>) super.delegate();
  }

  @Override
  public Comparator<? super E> comparator() {
    return delegate().comparator();
  }

  @Override
  SortedSet<E> createElementSet() {

@GwtIncompatible
abstract class ForwardingLock implements Lock {
  abstract Lock delegate();

  @Override
  public void lock() {
    delegate().lock();
  }

  @Override
  public void lockInterruptibly() throws InterruptedException {
    delegate().lockInterruptibly();
  }

  @Override
  public boolean tryLock() {
    return delegate().tryLock();
  }

  @Override

      e = null,
    )
  }

  /** A request body that fires events when it completes. */
  private inner class RequestBodySink(
    delegate: Sink,
    /** The exact number of bytes to be written, or -1L if that is unknown. */
    private val contentLength: Long,
  ) : ForwardingSink(delegate) {
    private var completed = false
    private var bytesReceived = 0L
    private var closed = false

    @Throws(IOException::class)

  @Override
  protected abstract BlockingQueue<E> delegate();

  @CanIgnoreReturnValue
  @Override
  public int drainTo(Collection<? super E> c, int maxElements) {
    return delegate().drainTo(c, maxElements);
  }

  @CanIgnoreReturnValue
  @Override
  public int drainTo(Collection<? super E> c) {
    return delegate().drainTo(c);
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this

                // release
                old.release(true);
            }
            if (this.delegate != null && this.delegateAcquired) {
                log.debug("Releasing delegate");
                this.delegateAcquired = false;
                this.delegate.release();
            }
        }
    }

    /**
     * @return tree connection with increased usage count
     */