code: public Observable<ServiceResponse<VirtualNetworkGatewayInner>> resetWithServiceResponseAsync(String resourceGroupName, String virtualNetworkGatewayName) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (virtualNetworkGatewayName == null) {
              throw new IllegalArgumentException("Parameter virtualNetworkGatewayName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          final String apiVersion = "2018-06-01";
          final String gatewayVip = null;
          Observable<Response<ResponseBody>> observable = service.reset(resourceGroupName, virtualNetworkGatewayName, this.client.subscriptionId(), gatewayVip, apiVersion, this.client.acceptLanguage(), this.client.userAgent());
          return client.getAzureClient().getPostOrDeleteResultAsync(observable, new TypeToken<VirtualNetworkGatewayInner>() { }.getType());
      }
docs: Resets the primary of the virtual network gateway in the specified resource group.
  
  @param resourceGroupName The name of the resource group.
  @param virtualNetworkGatewayName The name of the virtual network gateway.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request