using System;

using System.Linq;

using System.Net.Http;

using System.Threading.Tasks;

using System.Collections.Generic;

​

public class Program

{

    static HttpClient client = new HttpClient();

    public static async Task Main()

    {

        var sw = System.Diagnostics.Stopwatch.StartNew();

        var urls = new List<string>{

            "https://www.google.com/",

            "https://docs.microsoft.com/",

            "https://stackoverflow.com/",

            "https://dotnetfiddle.net/",            

            "https://twitter.com/",

            "https://app.getpocket.com/",

            "https://feedly.com/",

            "https://www.pluralsight.com/",

            "https://www.microsoft.com/",           

            "https://dou.ua/",

            "https://github.com/",

            "https://www.youtube.com/",

            "https://www.linkedin.com/"

        };

        var tasks = new List<Task<string>>(urls.Count);

        foreach (var url in urls)

        {

            var task = client.GetStringAsync(url);

            tasks.Add(task);

        }

​

        var results = await Task.WhenAll(tasks);

        Console.WriteLine(string.Join(", ", results.Select(x=>x[0])));

        sw.Stop();

        Console.WriteLine(sw.Elapsed);

    }

}