Support many proxy server

[khacluan]

When I used 1 proxy server, may be the proxy server is not working sometime
so I want to have many proxy server

EX: I have 3 proxy list server [proxy1.example.com, proxy2.example.com, proxy3.example.com]
First time I use proxy1.example.com
if proxy1.example.com died or refuse connection, I will trying proxy2.example.com, ...