Trying to use restify client with a proxy server

restify_client_proxy_server_test.js

//
// setup:
// npm i restify@3.0.3 request@2.58.0 http-proxy@1.11.1
//
var assert = require('assert');
var http = require("http");
var restify = require('restify');
var request = require('request');
var httpProxy = require('http-proxy');

var restifyDone = false;
var requestJsDone = false;
var proxyCallCount = 0;

function exitIfDone() {
    if (restifyDone && requestJsDone) {
        console.log("\nAll clients finished.");
        console.log("Proxy server called " + proxyCallCount + " time(s)");
        assert.equal(proxyCallCount, 2, "Expected proxy server to be called twice");
        process.exit();
    }
}

/**
 * Set up destination server that requests should get proxied to.
 */
http.createServer(function(req, res) {
    console.log("\nreceived request in destination server:", req.url);
    res.writeHead(200, {"Content-Type": "application/json"});
    res.write('{"hello": "world"}');
    res.end();
}).listen(8080);

console.log("Destination server listening on port 8080");

/**
 * Set up proxy server.
 */
var proxy = httpProxy.createProxyServer({});

var server = http.createServer(function(req, res) {
    console.log("\nreceived request in proxy server", req.url);
    proxyCallCount += 1;
    proxy.web(req, res, {target: 'http://' + req.headers.host});
});

console.log("Proxy server listening on port 5050");
server.listen(5050);

/**
 * Set up Restify client.
 */
var restifyClient = restify.createStringClient({
    url: 'http://127.0.0.1:8080',
    proxy: {
        host: '127.0.0.1',
        protocol: 'http:',
        port: 5050
    }
});

/**
 * Make request with Restify client
 */
restifyClient.get({path: '/?foo=bar&requester=restify'}, function(err, req, res, result) {
    if (err) {
        console.log(err);
        console.log(err.stack);
    }

    console.log("\nresponse: from Restify client:", result);
    restifyDone = true;
    exitIfDone();
});

/**
 * Make request with request.js client
 */
request.get("http://127.0.0.1:8080?foo=bar&requester=requestJs", {proxy: "http://127.0.0.1:5050"}, function(err, response, body) {
    if (err) {
        console.log(err);
        console.log(err.stack);
    }

    console.log("\nresponse from request.js client:", body);
    requestJsDone = true;
    exitIfDone();
});