public function release(\Octris\Db\Device\ConnectionInterface $cn)
    {
        $hash = spl_object_hash($cn);

        if (!isset($this->connections[$hash])) {
            throw new \Exception('Connection is not handled by this device');
        }

        array_push($this->pool[$this->connections[$hash]], $cn);
        unset($this->connections[$hash]);
    }