Stackless resumable functions

[bitwise via Digitalmars-d]

@ketmar

You know you may be kinda right about reusability though...

I am not as familiar with "await" as I am with coroutines, but I 
think the principal is similar. The Visual Studio team seems to 
have chosen to tackle stackless resumable routines and await at 
the same time, so there may be some reusability there. I couldn't 
say for sure though.

In any case, I don't think it would be hard to refactor my 
suggested implementation under the covers to facilitate something 
like await without hurting the user-facing functionality.