code: public void unregisterService(String serviceName, String providerId) {
          getServiceDirectoryClient().unregisterServiceInstance(serviceName, providerId);
          getCacheServiceInstances().remove(new ServiceInstanceToken(serviceName, providerId));
      }
docs: Unregister a ProvidedServiceInstance by serviceName and providerId.
  
  @param serviceName
  the serviceName of ProvidedServiceInstance.
  @param providerId
  the provierId of ProvidedServiceInstance.