Command line flag to simply ignore stale cache files

[Keno]

It would be useful while developing a package to have a command line flag that simply ignores the fact that a cache file is stale and just loads the package normally. Otherwise one has to wait for precompilation to finish, which takes longer than just loading the package.

[felipenoris]

+1.

[vtjnash]

My observation was that caching added ~15% to the load time of a package, which isn't quite enough for me to think this warrants adding another command line flag.

[Keno]

@timholy knows more about the performance issues, but with precompile directives that can easily go up to 2-3x.

[timholy]

To expand on both points, yes, I agree that under typical circumstances it's not a huge deal. As @Keno says, when you have lines like these that load files like this one (which, you'll note, is basically a no-op unless you're precompiling), then the cost of precompilation is too high to tolerate during development.