code: private void createActiveNetwork(final NetworkContext context, final Handler<AsyncResult<ActiveNetwork>> doneHandler) {
      final DefaultActiveNetwork active = new DefaultActiveNetwork(context.config(), DefaultCluster.this);
      vertx.eventBus().registerHandler(String.format("%s.%s.change", context.name(), context.name()), new Handler<Message<JsonObject>>() {
        @Override
        public void handle(Message<JsonObject> message) {
          String event = message.body().getString("type");
          if (event.equals("change") && message.body().getString("value") != null) {
            active.update(Contexts.<NetworkContext>deserialize(new JsonObject(message.body().getString("value"))));
          }
        }
      }, new Handler<AsyncResult<Void>>() {
        @Override
        public void handle(AsyncResult<Void> result) {
          if (result.failed()) {
            new DefaultFutureResult<ActiveNetwork>(new ClusterException(result.cause())).setHandler(doneHandler);
          } else {
            new DefaultFutureResult<ActiveNetwork>(active).setHandler(doneHandler);
          }
        }
      });
    }
docs: Creates and returns an active network.