code: public Observable<ExpressRouteCircuitInner> createOrUpdateAsync(String resourceGroupName, String circuitName, ExpressRouteCircuitInner parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, circuitName, parameters).map(new Func1<ServiceResponse<ExpressRouteCircuitInner>, ExpressRouteCircuitInner>() {
              @Override
              public ExpressRouteCircuitInner call(ServiceResponse<ExpressRouteCircuitInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates or updates an express route circuit.
  
  @param resourceGroupName The name of the resource group.
  @param circuitName The name of the circuit.
  @param parameters Parameters supplied to the create or update express route circuit operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request