htttpclient 伪装代理

我用httpclient来获取数据时，想伪装代理如下设置：$client->setUserAgent('Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; CIBA; MS-RTC LM 8; .NET4.0C; .NET4.0E; InfoPath.2; .NET CLR 2.0.50727)');可是不起作用用Snoopy伪装代理$snoopy->agent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.0.5)也不起作用请问问题怎么解决？