GoogleWebAuthorizationBroker.AuthorizeAsync CancellationToken无效

Question

有没有人能够让CancellationToken适用于AuthorizeAsync（）？

以下作品：

private void TryToAuthenticate()
{
  //Cancel the task BEFORE it starts
  m_cancelTokSrc.Cancel();

  //Start task
  Task<UserCredential> task = GoogleWebAuthorizationBroker.AuthorizeAsync(
    GoogleClientSecrets.Load(stream).Secrets,
    scopes,
    "user",
    m_cancelTokSrc.Token,
    new FileDataStore(m_CredentialFilePath, true))
    .ContinueWith((t) => AuthenticateCompleted(t));
}

private UserCredential AuthenticateCompleted(Task<UserCredential> task)
{
  //FIRES JUST FINE!
  UserCredential credentials = null;
  switch (task.Status)
  {
    case TaskStatus.Canceled:
      return null;
    case TaskStatus.RanToCompletion:
      credentials = task.Result;
      break;
  }

  return credentials;
}

以下不起作用：

private void TryToAuthenticate()
{
  //Start task
  Task<UserCredential> task = GoogleWebAuthorizationBroker.AuthorizeAsync(
    GoogleClientSecrets.Load(stream).Secrets,
    scopes,
    "user",
    m_cancelTokSrc.Token,
    new FileDataStore(m_CredentialFilePath, true))
    .ContinueWith((t) => AuthenticateCompleted(t));

  //Cancel the task AFTER it starts
  m_cancelTokSrc.Cancel();
}

private UserCredential AuthenticateCompleted(Task<UserCredential> task)
{
  //DOES NOT FIRE!!!
  UserCredential credentials = null;
  switch (task.Status)
  {
    case TaskStatus.Canceled:
      return null;
    case TaskStatus.RanToCompletion:
      credentials = task.Result;
      break;
  }

  return credentials;
}

似乎每当我请求授权时，它就会挂起等待来自Web浏览器的响应或其他内容。在循环中，它等待授权回复，它似乎永远不会检查cancelTokenSource.Token.IsCancellationRequested。有没有人成功取消过请求？