return super.set(t);
    }

    @CanIgnoreReturnValue
    @Override
    public boolean setException(Throwable t) {
      return super.setException(t);
    }
  }

  enum Impl {
    NEW {
      @Override
      <T> Facade<T> newFacade() {
        return new NewAbstractFutureFacade<T>();
      }
    },
    OLD {
      @Override
      <T> Facade<T> newFacade() {