var url = "https://raw.github.com/appcelerator/Documentation-Examples/master/HTTPClient/data/json.txt";

var xhr = Ti.Network.createHTTPClient({
enableKeepAlive: true,
    timeout:5000
});
//xhr.setEnableKeepAlive(true);

xhr.open("GET", url);
xhr.setRequestHeader("Connection","Keep-Alive");
xhr.send();