@Override
    public void storeState(final Configuration configuration) {
        super.storeState(configuration);
        configuration.setProperty(CLUSTER_COUNT_MEMORY_KEY, this.memoryKey);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/clustering/peerpressure/ClusterCountMapReduce.java