http://cdc.tencent.com/2017/06/29/%E5%9F%BA%E4%BA%8Eandroid-architecture-components%E7%9A%84%E5%BA%94%E7%94%A8%E6%9E%B6%E6%9E%84%E6%8C%87%E5%8D%97/#BCA
https://github.com/googlesamples/android-architecture-componentse Server CA
http://cdc.tencent.com/2017/06/29/%E5%9F%BA%E4%BA%8Eandroid-architecture-components%E7%9A%84%E5%BA%94%E7%94%A8%E6%9E%B6%E6%9E%84%E6%8C%87%E5%8D%97/#BCA
https://github.com/googlesamples/android-architecture-componentse Server CA