docs: protected void onServiceInstanceAvailable(ServiceInstance instance){
          String serviceName = instance.getServiceName();
          List<NotificationHandler> handlerList = new ArrayList<NotificationHandler>();
          synchronized (notificationHandlers) {
              if (notificationHandlers.containsKey(serviceName)) {
                  handlerList.addAll(notificationHandlers.get(serviceName));
              }
          }
          for (NotificationHandler h : handlerList) {
              h.serviceInstanceAvailable(instance);
          }
      }