I just noticed that new C-API functions are probably useless for Cython since I think it will have to maintain the CFrame stack, so not to enable "use_tracing" for the (Python) caller but the current (Cython) function. This then means that we own The current CFrame as well as its "use_tracing" field and don't need any help from CPython in order to change the state.

I'm not sure if this is any different for other users of the "use_tracing" field.