code: public Observable<VirtualNetworkGatewayInner> updateTagsAsync(String resourceGroupName, String virtualNetworkGatewayName, Map<String, String> tags) {
          return updateTagsWithServiceResponseAsync(resourceGroupName, virtualNetworkGatewayName, tags).map(new Func1<ServiceResponse<VirtualNetworkGatewayInner>, VirtualNetworkGatewayInner>() {
              @Override
              public VirtualNetworkGatewayInner call(ServiceResponse<VirtualNetworkGatewayInner> response) {
                  return response.body();
              }
          });
      }
docs: Updates a virtual network gateway tags.
  
  @param resourceGroupName The name of the resource group.
  @param virtualNetworkGatewayName The name of the virtual network gateway.
  @param tags Resource tags.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request