$q->enqueue( [ 'capture' => 'ls -la' ] );
...
$q->enqueue( [ 'exit' ] );
...
 while ((my $jackson = $q->dequeue())) 
    my( $action, @args ) = @$jackson;
    last if $action eq 'exit';
    if( $action eq 'capture' ){
      my $result ... @args ...