https://blog.wongcw.com/2018/12/26/ios-12-1-2-%e8%9c%82%e7%aa%a9%e7%b6%b2%e7%b5%a1%e5%95%8f%e9%a1%8c%e7%9a%84%e8%87%a8%e6%99%82%e4%bf%ae%e5%be%a9%e6%96%b9%e6%b3%95/