title: gremlin query with valueMap() and toList() takes time to get result
body: <p>I am using janus graph deployed in embedded mode. And i am using java. And firing following queries</p>
  
  <p>--> g.V().has('deleted',false).valueMap() //slow</p>
  
  <p>--> g.V().has('deleted',false).toList()  //slow</p>
  
  <p>the above query takes time after implementing composite indexes also</p>
  
  <p>--> g.V().has('deleted',false)  //fast</p>
  
  <p>above query is fast and use implemented composite index created on deleted key.</p>
  
  <p><strong>Also tried the same using java code</strong></p>
  
  <pre><code>        List&lt;Vertex&gt; list = new ArrayList&lt;&gt;();
  
          DateTime dt1 = new DateTime();
          JanusGraphQuery&lt;? extends JanusGraphQuery&gt; query = GraphClient.getJGraph().query();
          Iterator iterator = query.has("deleted",false).vertices().iterator();
          while(iterator.hasNext()) {
              Vertex next = (Vertex) iterator.next();
              getPropertyMapByVertex(next); //time consuming to convert vertex into Map.
              list.add(next);
          }
  
  
       public static Map&lt;String, Object&gt; getPropertyMapByVertex(Vertex vertex) {
      Map&lt;String, Object&gt; propertyMap = new HashMap&lt;&gt;();
      try {
          if (vertex != null) {
              Iterator&lt;VertexProperty&lt;Object&gt;&gt; properties = vertex.properties();
              if (properties != null) {
                  while (properties.hasNext()) {
                      Property&lt;Object&gt; property = properties.next();
                      propertyMap.put(property.key(), property.value());
                  }
                  propertyMap.put(GraphConstants.VERTEX_ID, vertex.id());
              }
          }
      } catch (Exception e) {
          logger.error("Exception in getPropertyMapByVertex : {}", ExceptionUtils.getStackTrace(e));
      }
      return propertyMap;
  }
  </code></pre>
  
  <p>do we have some way to fast "getPropertyMapByVertex" method or any other way to fire query and get data quickly using java.</p>