[ioquatix]

If you take a look, you'll see that I specifically designed the API to avoid the need for any global/thread local state.

So, the argument to `coroutine_transfer` is passed to the coroutine and the calling coroutine is returned from `coroutine_transfer`.

So, using %rax is not possible, because it's the return value. That being said, another register would be fine. So you think there is a performance improvement from putting the return address specifically into %rax as soon as possible?