I’d like to get some eyes on this: https://github.com/huge-success/sanic/pull/472
and see what we can do to get this completed. I don’t think we can reasonably add it for 18.12 LTS but I think we can get it in to 19.x, even though it may take some effort to update the code touches.
It looks like this had a lot of community support but did not ever complete the merge. It also got passes on reviews.