I think you missed an important point in the parent comment. You can override the allocation for C++ coroutines. You do have control over details like allocation.

C++ coroutines are so lightweight and customizable (for good and ill), that in 2018 Gor Nishanov did a presentation where he scheduled binary searches around cache prefetching using coroutines. And yes, he modified the allocation behavior, though he said it only resulted in a modest improvement on performance.