/**
* Renews a lock to extend its validity.
*
* Without renewing a lock, other clients may detect this client as stale and acquire a lock.
*
* @param string $id specific lock ID.
* @param string $token unique token provided during {@link lock()}.
* @return Promise promise fails if lock couldn't be renewed, otherwise resolves normally.
*/
public function renew($id, $token) : Promise
{
return $this->std->eval(self::RENEW, ["lock:{$id}"], [$token, $this->ttl]);
}
