RFC 5861 Cache-Control Extensions for Stale Content (async cache refresh)

[da2x]

Given the following header: The plugin should cache for 30 seconds (s-maxage) and can then serve the cached variant to subsequent requests for another 90 seconds (6 hours if the background server returns an error) while asynchronously refreshing the cached variant.

Cache-Control: max-age=60, s-maxage=30, stale-while-revalidate=90, stale-while-error=21600

https://tools.ietf.org/html/rfc5861#section-3

[nicolasazrak]

I'm not working actively on this project (just fixing bugs and replying issues), but, if you want, I'm accepting PRs :)

[cryptiklemur]

This is gaining more traction now. I don't have the technical know-how to PR this, but I would really love to see this!