onListen method

void onListen()

Implementation

void onListen() async {
  await controller.addStream(forward!(gqlRequest).handleError((error) {
    if(error != null && error is HttpLinkServerException){
      Http.Response httpResponse = error.response;
      if (httpResponse != null) {
          httpResponseHandler(null, httpResponse);
      }
    }
    throw error;
  }
  ));

  await controller.close();
}