Work in progress. Don't do this!! Avalon v.4.0 Hasn't been released yet.
In avalon.yml, under streaming, change "url_handler:" to "server:".
Add under streaming: "content_path:" and then the path to your rtmp stream folder.
It should look something like this:
streaming: server: :adobe content_path: /var/avalon/rtmp_streams stream_token_ttl: 20 rtmp_base: rtmp://mallorn.dlib.indiana.edu/avalon http_base: http://mallorn.dlib.indiana.edu/avalon