@Override
 public TransportClient getClient(Request request, RequestContext requestContext)
     throws ServiceUnavailableException {
   return _balancer.getClient(request, requestContext);
 }
 @Override
 public void shutdown(PropertyEventThread.PropertyEventShutdownCallback shutdown) {
   _balancer.shutdown(shutdown);
 }
 @Override
 public ServiceProperties getLoadBalancedServiceProperties(String serviceName)
     throws ServiceUnavailableException {
   return _balancer.getLoadBalancedServiceProperties(serviceName);
 }
 @Override
 public void start(Callback<None> callback) {
   _balancer.start(callback);
 }