sub count_up {
        $mw->update;
        my $progress = 0;
        warn "after \$progress init($counter):\n";
        Dump($progress);
        $pb->configure(
                -from => 0,
                -to   => 20,
                -variable => \$progress,  ## store the reference.
        );

        my $cnt = 0;
        print "\$cnt=$cnt; \$progress=$progress\n";

        for (1) {
                $progress++;
                warn "\$progreess in for() loop($counter):\n";
                Dump($progress);
                $cnt++ unless ($_ % 2);
                $mw->update;
        }
        $counter++;
        $mw->update;
}