code: public CassandraJavaPairRDD<K, V> toEmptyCassandraRDD() {
          CassandraRDD<Tuple2<K, V>> newRDD = rdd().toEmptyCassandraRDD();
          return wrap(newRDD);
      }
docs: Produces the empty CassandraRDD which has the same signature and properties, but it does not
  perform any validation and it does not even try to return any rows.