public function onWorkerHandlerMessage(MessageInterface $msg)
    {
        $this->workerHandlerReady = true;
        $this->worker->touch();

        if ($msg instanceof Destroy) {
            $this->worker->setState(Worker::INVALID);

            return;
        }

        if ($msg instanceof ExecuteJobRequest) {
            $this->startJob($msg);

            return;
        }

        if ($msg instanceof HeartbeatResponseWorkerhandler) {
            $this->handleHeartbeatResponse();

            return;
        }

        $this->getLogger()->error('Unknown worker-handler response: '.get_class($msg).'.');
    }