protected function getPriority($command, array $params)
    {
        $priority = new EventQueuePriority;
        $priority->value = $this->priorities[$command];
        $priority->timestamp = (int) (microtime(true) * 10000);
        if ($priority->timestamp <= $this->lastTimestamp) {
            $priority->timestamp = $this->lastTimestamp + 1;
        }
        $this->lastTimestamp = $priority->timestamp;
        return $priority;
    }