public function flush()
    {
        if ($this->doNotTrack) {
            return;
        }

        if (empty($this->queue)) {
            return;
        }

        if ($this->mergePackets) {
            $this->send(implode("\n", $this->queue));
        } else {
            foreach ($this->queue as $data) {
                $this->send($data);
            }
        }
        $this->queue = array();
        $this->queueSize = 0;
    }