如何检测App启动时间?

在 Xcode 中 Edit scheme -> Run -> Auguments 将环境变量DYLD_PRINT_STATISTICS 设为 1。

控制台输出的内容如下
Total pre-main time: 72.48 milliseconds (100.0%)
dylib loading time: 12.07 milliseconds (16.6%)
rebase/binding time: 28.84 milliseconds (39.7%)
ObjC setup time: 3.63 milliseconds (5.0%)
initializer time: 27.85 milliseconds (38.4%)
slowest intializers :
libSystem.B.dylib : 7.07 milliseconds (9.7%)
libBacktraceRecording.dylib : 19.06 milliseconds (26.2%)