string(247) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%B8%A6%E5%AE%BD%E4%B8%8E%E6%AF%94%E7%89%B9%E7%8E%87%E7%9A%84%E5%85%B3%E7%B3%BB => Failed to connect to 14.18.117.71 port 38069: Connection refused"
带宽与比特率的关系
