lastBookmark () {
    return this.lastBookmarks()
  }
Returns the bookmarks received following the last successfully completed query, which is executed
either in an {@link RxTransaction} obtained from this session instance or directly through one of
the {@link RxSession#run} method of this session instance.

If no bookmarks were received or if this transaction was rolled back, the bookmarks value will not be
changed.

@deprecated This method will be removed in 6.0 version. Please, use {@link RxSession#lastBookmarks} instead.

@public
@returns {string[]}