code: public Observable<LocalNetworkGatewayInner> createOrUpdateAsync(String resourceGroupName, String localNetworkGatewayName, LocalNetworkGatewayInner parameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, localNetworkGatewayName, parameters).map(new Func1<ServiceResponse<LocalNetworkGatewayInner>, LocalNetworkGatewayInner>() {
              @Override
              public LocalNetworkGatewayInner call(ServiceResponse<LocalNetworkGatewayInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates or updates a local network gateway in the specified resource group.
  
  @param resourceGroupName The name of the resource group.
  @param localNetworkGatewayName The name of the local network gateway.
  @param parameters Parameters supplied to the create or update local network gateway operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request