d to be called in a waitable procedure
invoked by a-sync.  It is the single-threaded corollary of
await-glib-generator-in-thread.  This means that (unlike with
await-glib-generator-in-thread) while &rsquo;generator&rsquo; is running other
events in the main loop will not make progress, so blocking calls
(other than to the yield procedure) should not be made in
&rsquo;generator&rsquo;.
</p>
<p>This procedure must (like the a-sync procedure) be called in the same
thread as that in which the default glib main 