I'm not aware of the technical how, but the Arch infrastructure seems to measure this successfully; a hook into this data might be a great way for the two to interoperate (so that Cloudflare always serves the freshest cache/mirrors). https://www.archlinux.org/mirrors/status/

The relevant code can be found here I believe: https://github.com/archlinux/archweb/blob/master/mirrors/man...