Hi, and thanks for interest in JR.
As of right now there's no set plans for including async functionality in a future version of JR. It requires change to the API and a lot of time.
If there was greater demand (and I had more time/energy) for it I'd love to support it, but in my own opinion, much of the beauty of an ORM goes away when dealing with callbacks and so on anyway.
Please let me know if this is useful.
Thanks again!