To be honest I find it a bit weird to want this specific API have anything to do with cancellation — it is for contexts which are not within the task infrastructure so by itself it can’t do anything about that.
In [Pitch #2] Structured Concurrency - #116 by ktoso I propose additions or reshaping of the Task APIs such that one would be able to get a Task object, and if one wanted to one could then check it from wherever — including implementations using *Continuations. That’s about as much as we can achieve I think.