protected function getJobsEarliestTryAt()
    {
        $tryAt = date('Y-m-d H:i:s');

        foreach ($this->jobs as $job) {
            if (!$job->isFinished() && Helper::datetimeLT($job->getTryAt(), $tryAt)) {
                $tryAt = $job->getTryAt();
            }
        }

        return $tryAt;
    }