async gio test

In order to understand how to use the asynchronous API of gio, I have cooked a small test. It was a little hard to figure out the use of the API, mostly because I could not find implementations using Google’s codesearch, neither doing grand-greps ™ on my jhbuild’s directory of checkouts.

I hope this little test be useful for those who are trying to use gio in their async operations.