private function acquire_lock($acquire_timeout = 10) {
		$identifier = (string)Uuid::uuid4();

		$end = time() + $acquire_timeout;
		while (time() < $end) {
			$res = $this->client->setnx('lock:' . $this->name, $identifier);
			if ($res) {
				return $identifier;
			}
			sleep(0.001);
		}
		return false;
	}