Using stampede with compress middleware.

[rassakhatsky]

I'm trying to figure out how to use stampede on a single route level with compress middleware.
The issue is that compress middleware adds a Content-Encoding header before stampede will cache it. So on the next request data with Content-Encoding would be returned as is, because compress middleware would think that data has been compressed.
I'm willing to raise a PR fix, but not fully sure about direction. Is it an issue with compression logic or caching?