http://android-developers.googleblog.com/2017/10/effective-phone-number-verification.html
origin - http://www.pipiscrew.com/?p=11105 firebase-phone-number-verification
http://android-developers.googleblog.com/2017/10/effective-phone-number-verification.html
origin - http://www.pipiscrew.com/?p=11105 firebase-phone-number-verification