Re-encode mid stream to allow users to join stream after it has begun #114

I have tried to let a user join a stream mid-stream by saving the initial headers and then waiting for the next chunk to come up, but I can't make it work.

I tried changing the start and end by calculating the last end from the headers, and then setting a new start and end on any upcoming data. It didn't work.

Does someone have an idea if what I trying to do is possible? If I manage to solve this I will be able to solve a lot of scaling issues in a setup I am working on :-)