private VerticleHolder getVerticleHolder() {
   Context context = vertx.getContext();
   if (context != null) {
     VerticleHolder holder = (VerticleHolder) context.getDeploymentHandle();
     return holder;
   } else {
     return null;
   }
 }
 // Must be synchronized since called directly from different thread
 private void addVerticle(Deployment deployment, Verticle verticle, VerticleFactory factory) {
   String loggerName =
       "org.vertx.deployments." + deployment.name + "-" + deployment.verticles.size();
   Logger logger = LoggerFactory.getLogger(loggerName);
   Context context = vertx.getContext();
   VerticleHolder holder =
       new VerticleHolder(
           deployment, context, verticle, loggerName, logger, deployment.config, factory);
   deployment.verticles.add(holder);
   context.setDeploymentHandle(holder);
 }