function giveBuiltInQueue(iQueueDriver $queueDriver)
    {
        if ($this->builtinQueue)
            throw new exImmutable(sprintf(
                'Built-in Queue (%s) is given.'
                , \Poirot\Std\flatten($this->builtinQueue)
            ));


        $this->builtinQueue = $queueDriver;
        return $this;
    }