docs: public void registerInstance(ProvidedServiceInstance instance){
          String body = _serialize(instance);
          HttpResponse result = invoker.invoke(toInstanceUri(instance.getServiceName(), instance.getProviderId()), body,
                  HttpMethod.POST);
  
          if (result.getHttpCode() != HTTP_CREATED) {
              throw new ServiceException(ErrorCode.REMOTE_DIRECTORY_SERVER_ERROR,
                      "HTTP Code is not OK, code=%s",result.getHttpCode());
          }
      }