How to send json rather than form encoded with superMap

I feel like I must be missing something, but I can’t seem to find the way to send json post/put data for create/update methods in the super map. It does seem from docs that it might be hard-coded to sending form params?

https://connect.canjs.com/doc/can-connect|data-url.html

POST and PUT requests put data that is not templated in the URL in POST or PUT body as form encoded data.

So I found this: https://github.com/donejs/bitballs/blob/master/public/util/prefilter.js

but feels clunky?

Yeah, this is legacy that is going to change for canjs 3.0