*/
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */

    }
  }

  static final LazyLogger log = new LazyLogger(AbstractFuture.class);

  // A heuristic for timed gets. If the remaining timeout is less than this, spin instead of
  // blocking. This value is what AbstractQueuedSynchronizer uses.
  private static final long SPIN_THRESHOLD_NANOS = 1000L;

  private static final AtomicHelper ATOMIC_HELPER;

  static {
    AtomicHelper helper;
    Throwable thrownUnsafeFailure = null;

/**
 * GWT emulated version of {@link com.google.common.collect.ImmutableSet}. For the unsorted sets,
 * they are thin wrapper around {@link java.util.Collections#emptySet()}, {@link
 * Collections#singleton(Object)} and {@link java.util.LinkedHashSet} for empty, singleton and
 * regular sets respectively. For the sorted sets, it's a thin wrapper around {@link
 * java.util.TreeSet}.
 *
 * @see ImmutableSortedSet
 * @author Hayward Chan
 */

    } catch (Throwable t) {
      threadUnexpectedException(t);
    }
  }

  //     /**
  //      * Spin-waits up to LONG_DELAY_MS until flag becomes true.
  //      */
  //     public void await(AtomicBoolean flag) {
  //         await(flag, LONG_DELAY_MS);
  //     }

  //     /**
  //      * Spin-waits up to the specified timeout until flag becomes true.
  //      */

    }

    /*
     * These gymnastics are a little confusing. Basically this class has neither legacy nor
     * non-legacy behavior; it just needs to let the behavior of the backing converter shine
     * through. So, we override the correctedDo* methods, after which the do* methods should never
     * be reached.
     */

    @Override
    protected A doForward(B b) {
      throw new AssertionError();

    ArrayList<E> list = new ArrayList<>(capacity);
    Collections.addAll(list, elements);
    return list;
  }

  /**
   * Creates a <i>mutable</i> {@code ArrayList} instance containing the given elements; a very thin
   * shortcut for creating an empty list then calling {@link Iterables#addAll}.
   *
   * <p><b>Note:</b> if mutability is not required and the elements are non-null, use {@link

   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */

     * been intended for something else, so don't clear it.
     */
    boolean restoreInterruptedBit = false;
    int spinCount = 0;
    // Interrupting Cow Says:
    //  ______
    // < Spin >
    //  ------
    //        \   ^__^
    //         \  (oo)\_______
    //            (__)\       )\/\
    //                ||----w |
    //                ||     ||
    Runnable state = get();

    Collections.addAll(set, elements);
    return set;
  }

  /**
   * Creates a <i>mutable</i> {@code HashSet} instance containing the given elements. A very thin
   * convenience for creating an empty set then calling {@link Collection#addAll} or {@link
   * Iterables#addAll}.
   *
   * <p><b>Note:</b> if mutability is not required and the elements are non-null, use {@link

      super.begin();
    }
  }

  /**
   * Because Thread.interrupt() can invoke arbitrary code, it can be slow (e.g. perform IO). To
   * protect ourselves from that we want to make sure that tasks don't spin too much waiting for the
   * interrupting thread to complete the protocol.
   */
  /*
   * This test hangs (or maybe is just *very* slow) under Android.
   *