@Override
    public Iterator iterator() {
        return IteratorUtils.map(this.getKeys(), k -> new Pair<>(k, this.getProperty(k)));
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/HadoopConfiguration.java