How to use the can-connect/helpers/.deferred function in can-connect

module.exports = function (o) {
	var xhr = $.xhr(), timer, n = 0;
	var deferred = helpers.deferred();

	o = helpers.extend({ userAgent: "XMLHttpRequest", lang: "en", type: "GET", data: null, dataType: "application/x-www-form-urlencoded" }, o);
	if (o.timeout) {
		timer = setTimeout(function () {
			xhr.abort();
			if (o.timeoutFn) {
				o.timeoutFn(o.url);
			}
		}, o.timeout);
	}
	xhr.onreadystatechange = function () {
		if (xhr.readyState === 4) {
			if (timer) {
				clearTimeout(timer);
			}
			if (xhr.status < 300) {