public static void registerEdgeCreation(final CallbackRegistry<Event.EdgeAddedEvent> callbackRegistry,
                                            final Traversal.Admin<Object, Object> traversal,
                                            final Edge addedEdge){
        if (hasAnyCallbacks(callbackRegistry)) {
            final Event.EdgeAddedEvent vae = createEdgeAddedEvent(traversal, addedEdge);
            callbackRegistry.getCallbacks().forEach(c -> c.accept(vae));
        }
    }
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