Honestly, I've never missed the shared mutable environment approach one bit. It might have been marginally faster, but I'd trade a whole bunch of performance fo

Honestly, I've never missed the shared mutable environment approach one bit. It might have been marginally faster, but I'd trade a whole bunch of performance for consistency (and the optimizations mean there's not much of a performance difference). Moreover, most of the time spent in CI is not container/VM overhead, but rather crappy Docker images, slow toolchains, slow tests, etc.