[Vala] Coroutines in vala: libtask, pthread or simply async?

[Luca Dionisi <luca dionisi gmail com>]

I just came from reading the tutorial at http://live.gnome.org/Vala/Tutorial
It is very comprehensive, kudos to the authors.

I don't understand, though, the way of using the async methods as
explained there.
More precisely I don't understand whether this feature is what I am looking for.

I am in need of something similar to the tasklet concept of python
stackless, if you know.
That is, a way of scheduling several (a lot of) routines which will
cooperatively run in pseudo-parallel. All in a single o.s. thread.
Co-routines[1].

Is this feature of GIO, which async methods in vala are based upon, an
approach to do what I need?
Or do I really want to look at gnu portable thread[2]? And if so,
anyone already used it in vala?
Or is libtask[3] the only real solution?

--Luca

[1] http://en.wikipedia.org/wiki/Coroutine
[2] http://www.gnu.org/software/pth/
[3] http://swtch.com/libtask/