docs: @Override
      public ServiceInstance queryInstanceByMetadataKey(ServiceInstanceQuery query)
              throws ServiceException {
          
          ServiceInstanceUtils.validateManagerIsStarted(isStarted.get());
          validateServiceInstanceMetadataQuery(query);
  
          ServiceInstanceLoadBalancer lb = lbManager.getDefaultLoadBalancer();
          return lb.vote(queryInstancesByMetadataKey(query));
      }