code: static HazelcastInstance getHazelcastInstance(Vertx vertx) {
      VertxInternal vertxInternal = (VertxInternal) vertx;
      ClusterManager clusterManager = vertxInternal.clusterManager();
      if (clusterManager != null) {
        Class<?> clazz = clusterManager.getClass();
        Field field;
        try {
          field = clazz.getDeclaredField("hazelcast");
          field.setAccessible(true);
          return HazelcastInstance.class.cast(field.get(clusterManager));
        } catch (Exception e) {
          return null;
        }
      }
      return null;
    }
docs: Returns the Vert.x Hazelcast instance if one exists.
  
  @param vertx The current Vert.x instance.
  @return The Vert.x Hazelcast instance if Vert.x is clustered.