Could you support tcp ping through proxy?

[gaorizhong]

There is plenty of scenarios that I need to test latency to server through proxy without ICMP supported. Could you please add this feature？ 增加代理--proxy 选项可以测试通过代理链接的延时

[paradiseduo]

没太看懂，你是想通过代理服务器测试延时吗（使用代理池测试某一个IP的延迟）？