public static void migrateGraph(final Graph fromGraph, final Graph toGraph) throws IOException {
        migrateGraph(fromGraph, toGraph, fromGraph.io(gryo()).reader().create(), toGraph.io(gryo()).writer().create());
    }
Use Gryo to pipe the data from one graph to another graph.  Uses readers and writers generated from each
{@link Graph} via the {@link Graph#io(Io.Builder)} method.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/GraphMigrator.java