Nice idea, that could actually work, I'll try that in a minute.

I was just hoping that there was some kind of $condvar->send/recv mechanism that supported lock()/unlock() so that I could write something like

       
$condvar->lock();
http_get "http://blah", sub { $condvar->unlock();
     print $_[1] };
[download]

sub timer_callback {
    $condvar->lock();
    # ...
    $condvar->unlock();
}
[download]