protected function processIteration(array &$job)
    {
        try {
            $handlers = $this->getHandlers();
            $callback = Handler::get($handlers, $job['id'], 'process');
            call_user_func_array($callback, array(&$job));
        } catch (Exception $ex) {
            $job['status'] = false;
            $job['errors']++;
        }
    }