code: public Observable<NetworkInterfaceInner> beginCreateOrUpdateAsync(String resourceGroupName, String networkInterfaceName, NetworkInterfaceInner parameters) {
          return beginCreateOrUpdateWithServiceResponseAsync(resourceGroupName, networkInterfaceName, parameters).map(new Func1<ServiceResponse<NetworkInterfaceInner>, NetworkInterfaceInner>() {
              @Override
              public NetworkInterfaceInner call(ServiceResponse<NetworkInterfaceInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates or updates a network interface.
  
  @param resourceGroupName The name of the resource group.
  @param networkInterfaceName The name of the network interface.
  @param parameters Parameters supplied to the create or update network interface operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the NetworkInterfaceInner object