s a value will
cause &rsquo;proc&rsquo; to execute in the default glib main loop.
</p>
<p>&rsquo;proc&rsquo; should be a procedure taking a single argument, namely the
value yielded by the generator.  If the optional &rsquo;handler&rsquo; argument is
provided, then that handler will be run in the default glib main loop
if &rsquo;generator&rsquo; throws; otherwise the program will terminate if an
unhandled exception propagates out of &rsquo;generator&rsquo;.  &rsquo;handler&rsquo; should
take the same argume