string(304) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BD%91%E7%BB%9C%E4%BC%A0%E8%BE%93%E9%80%9F%E7%8E%87%E7%9A%84%E5%8D%95%E4%BD%8D%E6%98%AFbps%E5%AE%83%E8%A1%A8%E7%A4%BA%E4%BB%80%E4%B9%88 => Failed to connect to 14.18.117.71 port 38220: Connection refused"
网络传输速率的单位是bps它表示什么
