string(258) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BB%80%E4%B9%88%E6%98%AF%E5%B8%A6%E5%AE%BD%E5%90%9E%E5%90%90%E9%87%8F%E6%97%B6%E5%BB%B6 => Failed to connect to 101.89.159.206 port 38075: Connection refused"
什么是带宽吞吐量时延
