anchor.diff:  
   GraphStrategy strategy = new SubgraphStrategy(vertexCriterion, edgeCriterion);
   StrategyWrappedGraph sg = new StrategyWrappedGraph(g);
  -sg.strategy().setGraphStrategy(strategy);
  +sg.getStrategy().setGraphStrategy(strategy);
   
   // all vertices are here
   System.out.println("" + sg.V().count() + " of " + g.V().count() + " vertices");
  
positive.code: * Reading and writing a single `Edge`
  
  In all cases, these methods operate in the currency of `InputStream` and `OutputStream` objects, allowing graphs and their related elements to be written to and read from files, byte arrays, etc.
  
  
  GraphML Reader/Writer
  ~~~~~~~~~~~~~~~~~~~~~
  
negative.code: ==>PartitionGraphStrategy
  gremlin> sg = new StrategyWrappedGraph(g)
  ==>strategywrappedgraph[tinkergraph[vertices:0 edges:0]]
  gremlin> sg.getStrategy().setGraphStrategy(strategy)
  ==>null
  ----
  
  