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