i.e. so users could swap out the Django Channels / Redis backend for - [AWS API gateway](https://aws.amazon.com/blogs/compute/announcing-websocket-apis-in-amazon-api-gateway/) - [Pusher Channels](https://pusher.com/channels) in a similar way to Wagtail's [pluggable backends for search](http://docs.wagtail.io/en/v2.4/topics/search/backends.html#rolling-your-own).