edure 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 event loop thread 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 arguments as a guile catch handler (this is implemented
using catch).
</p>
<p>This procedure calls &rsquo;await&rsquo; and will return w