title: How to use HttpClient to keep login state for furture process after the app was restarted?
body: <p>My app use HttpPost to login a discuss so I can get some pages that must need to be loged in used the same httpClient instance .
  But if my app was quit and restart again after sometime. Can I use the httpClient response that keep me the state that I have loged in?
  If can't,what should I do when the app quit?
  save the cookie?
  Or can I save the httpClient instance?
  How to do that?
  Thank you!</p>