/**
     * The elements of a {@link ConcurrentlyMutatedList} are added and removed over time. This
     * method returns every state that the list has passed through at some point.
     */
    Set<List<E>> getAllStates();
  }

  /**
   * Returns a {@link ConcurrentlyMutatedList} that performs the given operations as its concurrent

    /**
     * The elements of a {@link ConcurrentlyMutatedList} are added and removed over time. This
     * method returns every state that the list has passed through at some point.
     */
    Set<List<E>> getAllStates();
  }

  /**
   * Returns a {@link ConcurrentlyMutatedList} that performs the given operations as its concurrent