code: public Observable<ExpressRouteCircuitInner> beginUpdateTagsAsync(String resourceGroupName, String circuitName, Map<String, String> tags) {
          return beginUpdateTagsWithServiceResponseAsync(resourceGroupName, circuitName, tags).map(new Func1<ServiceResponse<ExpressRouteCircuitInner>, ExpressRouteCircuitInner>() {
              @Override
              public ExpressRouteCircuitInner call(ServiceResponse<ExpressRouteCircuitInner> response) {
                  return response.body();
              }
          });
      }
docs: Updates an express route circuit tags.
  
  @param resourceGroupName The name of the resource group.
  @param circuitName The name of the circuit.
  @param tags Resource tags.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ExpressRouteCircuitInner object