In file HttpProxySocketProvider line 120 the header doesnt look like a valid RFC2817 header.
request.setHeaderBegin("CONNECT " + protocol + host + ":" + port + " HTTP/1.0");
Normally it should be
CONNECT server.example.com:80 HTTP/1.1
The protocol in the header seems to be incorrect to me.
You are right. I won't change it since I cannot/will not test it.
Working patches are welcome.