sources 包括 sources0(比如点击事件、performSelector)、sources1(基于port的)

点击事件(打断点lldb输入bt) performSelector(打断点lldb输入bt)

参考:https://www.jianshu.com/p/6453468ef06c

参考:https://www.jianshu.com/p/1d79a7d631c8