I was wondering if there is a quick and efficient way to determine the Time from opening an app to when it's fully loaded.
That really won't work because it doesn't deal with iOS loading and launching your app.
The best you should do is log a timestamp in
main but again, this won't include the time it takes iOS to load and launch the app to the point that
main is called.
Any timing you do will be from that point forward which may still be useful depending on your goal.