throw new InvalidObjectException("Use SerializationProxy");
  }

  /**
   * The actual object that gets serialized. Unfortunately, readResolve() doesn't get called when a
   * circular dependency is present, so the proxy must be able to behave as the map itself.
   */
  abstract static class AbstractSerializationProxy<K, V> extends ForwardingConcurrentMap<K, V>
      implements Serializable {

      return new Failure(t);
    }
  }

  /**
   * An inlined private copy of {@link Uninterruptibles#getUninterruptibly} used to break an
   * internal dependency on other /util/concurrent classes.
   */
  @ParametricNullness
  private static <V extends @Nullable Object> V getUninterruptibly(Future<V> future)
      throws ExecutionException {
    boolean interrupted = false;

    throw new InvalidObjectException("Use SerializationProxy");
  }

  /**
   * The actual object that gets serialized. Unfortunately, readResolve() doesn't get called when a
   * circular dependency is present, so the proxy must be able to behave as the map itself.
   */
  abstract static class AbstractSerializationProxy<K, V> extends ForwardingConcurrentMap<K, V>
      implements Serializable {