private static Event.EdgeAddedEvent createEdgeAddedEvent(final Traversal.Admin<Object, Object> traversal,
                                                             final Edge addedEdge){
        final EventStrategy eventStrategy = forceGetEventStrategy(traversal);
        return new Event.EdgeAddedEvent(eventStrategy.detach(addedEdge));
    }
Register a vertex property addition event with the callback registry.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/util/event/EventUtil.java