Using codegen to support async

[tim-schilling]

There's a DEP to support async by generating the sync version of code. There's an idea of trialing it on a third party package before using it with Django core. I wanted to see what @django-commons/django-debug-toolbar thought about it doing that trial here.

https://forum.djangoproject.com/t/dep-draft-request-for-shepherd-unasyncify-codegen/36038/6

[matthiask]

I think our code might be a little bit too tricky in some places around instrumentation to really gain much from this, but I'm happy to be proven wrong.

I don't think pushing this ahead would be a priority for me at this time, but I'll gladly help out if I can.

[tim-schilling]

That's a good point on the instrumentation. I do think the Middleware would benefit from this. Basically any place where @salty-ivy had to refactor work to get an async version to work.