I am working on a Redis backend for storing the session.

The way to do this, I imagine, is to create a separate Middleware to manage a connection pool to Redis. This Middleware would store a connection in the State that the Session backend can use. I don't see any other way that the Redis connections could be handled, correct me if I'm wrong.

In order for the backend to use the connection it needs to have access to the State. Currently, this isn't passed in. It would be great if it could be!

I have knocked up a quick proof of concept here: https://github.com/FungusHumungus/gothamboogy/blob/master/src/redis.rs, and have a tentative pull request available - if you think this is the correct way to solve this issue. I'll submit it in a minute for your perusal.

This is probably also relevant to #69.