public default <K, V> Iterator<KeyValue<K, V>> writeMemoryRDD(final Configuration configuration, final String memoryKey, final JavaPairRDD<K, V> memoryRDD) {
        return Collections.emptyIterator();
    }
Write the sideEffect memoryRDD to an output location. The {@link Configuration} maintains the specified location via {@link Constants#GREMLIN_HADOOP_OUTPUT_LOCATION}.
The default implementation returns an empty iterator.

@param configuration the configuration of the Spark job
@param memoryKey     the memory key of the memoryRDD
@param memoryRDD     the memoryRDD
@param <K>           the key class of the RDD
@param <V>           the value class of the RDD
@return the {@link KeyValue} iterator to store in the final resultant {@link Memory}.
spark-gremlin/src/main/java/org/apache/tinkerpop/gremlin/spark/structure/io/OutputRDD.java