private String toResultString(final Traversal traversal) {
        return (String) IteratorUtils.stream(traversal).map(Object::toString).collect(Collectors.joining(",", "[", "]"));
    }
Services may need to specify traverser requirements.
tinkergraph-gremlin/src/test/java/org/apache/tinkerpop/gremlin/tinkergraph/structure/TinkerGraphServiceTest.java