public function isDue($currentTime = null)
    {
        if (null === $currentTime || 'now' === $currentTime) {
            $currentDate = date('Y-m-d H:i:s');
            $currentTime = strtotime($currentDate);
        } elseif ($currentTime instanceof DateTime) {
            $currentDate = $currentTime->format('Y-m-d H:i:s');
            $currentTime = strtotime($currentDate);
        } else {
            $currentTime = new DateTime($currentTime);
            $currentTime->setTime($currentTime->format('H'), $currentTime->format('i'), $currentTime->format('s'));
            $currentDate = $currentTime->format('Y-m-d H:i:s');
            $currentTime = $currentTime->getTimeStamp();
        }

        return $this->getNextRunDate($currentDate, 0, true)->getTimestamp() == $currentTime;
    }