     }
   }
 
-  // MARK: NSURLSessionDataDelegate
+  // MARK: URLSessionDataDelegate
 
   func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive response: URLResponse, completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {
     if status == .canceling { return }

  func urlSessionDidFinishEvents(forBackgroundURLSession session: URLSession) {
  }

  // MARK: NSURLSessionTaskDelegate

  func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
    if let error = error {

    }
  }

  // MARK: URLSessionDelegate

  func urlSession(_ session: URLSession, didBecomeInvalidWithError error: Error?) {
    status = .invalid
