public function cancel()
{
$this->stopped();
$this->setStatus(Job::STATUS_CANCELLED);
$this->redis->zadd(Queue::redisKey($this->queue, 'cancelled'), time(), $this->payload);
Stats::incr('cancelled', 1);
Stats::incr('cancelled', 1, Queue::redisKey($this->queue, 'stats'));
Event::fire(Event::JOB_CANCELLED, $this);
}