http://lingyuncxb.com/2018/01/30/iOS启动优化/
https://hanson647.com/2018/05/30/2018/iOS包大小计算备忘/
http://blog.cnbang.net/tech/2296/
https://juejin.im/entry/57a3fedc165abd0061440e94
https://blog.csdn.net/u011342466/article/details/79740086 Sqlite数据库和线程安全
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/EncapsulatingData/EncapsulatingData.html 原子和非原子实现上面的区分