string(321) "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%E5%8D%95%E4%BD%8D%E5%92%8C%E9%80%9F%E7%8E%87%E5%8D%95%E4%BD%8D%E7%9A%84%E6%8D%A2%E7%AE%97%E5%85%AC%E5%BC%8F%E6%98%AF%E4%BB%80%E4%B9%88 => Failed to connect to 125.88.227.171 port 38062: Connection refused"
带宽单位和速率单位的换算公式是什么
