closure

gistfile1.js

#!/usr/bin/env node

var i = 0,
	n = 10,
	times = {},
	http = require('http');

for(; i < n; i++) {
	reqone(i + 1);
}

function reqone(i) {
	var start = +new Date,
		opts = {
			host: 'dev',
			path: '/sleepms.php?n=' + i
		};

	function closure() {
		return callback;
	}

	function callback(response) {
		var str = '';

		response.on('data', function(chunk) {
			str += chunk;
		});

		response.on('end', function() {
			times[i] = (+new Date) - start;
			if(i >= n) {
				console.log(times);
			}
		});
	}

	http.request(opts, closure()).end();
}