c# множество асинхронных HttpWebRequest

Question

Пытаюсь сделать множество асинхронных запросов HttpWebRequest. Подготовил мини тест:

class Program
{
    static void Main(string[] args)
    {
        Test();
        Console.ReadLine();
    }

    public static async void Test()
    {
        for (int i = 0; i < 10; i++)
        {
            int val = i;
            await Task.Run(() => WR(val));
        }
    }

    static async void WR(int msg)
    {
        Console.WriteLine(msg + " begin");

        string url = "https://stackoverflow.com";
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "GET";
        var response = (HttpWebResponse)await Task.Factory.FromAsync<WebResponse>
                (request.BeginGetResponse, request.EndGetResponse, null);

        Console.WriteLine(msg + " status code: " + response.StatusCode);
        Console.WriteLine(msg + " end");
    }
}

Но вот что получилось:

0 begin
1 begin
2 begin
3 begin
4 begin
5 begin
6 begin
7 begin
8 begin
9 begin
0 status code: OK
0 end
1 status code: OK
1 end

А после 1 end вообще ничего не происходит. Где-то через 30 секунд в output вылазит:

The thread 0x6634 has exited with code 0 (0x0).
The thread 0x5620 has exited with code 0 (0x0).
The thread 0x4d08 has exited with code 0 (0x0).
The thread 0x39b8 has exited with code 0 (0x0).
The thread 0x3454 has exited with code 0 (0x0).
The thread 0x99c has exited with code 0 (0x0).
The thread 0x6be0 has exited with code 0 (0x0).

Но никаких ошибок в дебаге не вываливается. Подскажите где я ошибся и как исправить?

UPDATE: Затык происходит при запуске в Visual Studio. Интересно что с включенным Fiddler все работает нормально.

Answer 1

Переписал немного ваш код. Все прекрасно работает

void  Main()
{
    Test();
    Console.ReadLine();
}

public static async Task Test()
{
    var tasks = new List<Task>();
    for (int i = 0; i < 10; i++)
    {
        int val = i;
        var task =  WR(val);
        tasks.Add(task);
    }
    await Task.WhenAll(tasks);
}

static async Task WR(int msg)
{
    Console.WriteLine(msg + " begin");

    string url = "https://stackoverflow.com";
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
    request.Method = "GET";
    var response = (HttpWebResponse)await Task.Factory.FromAsync<WebResponse>
            (request.BeginGetResponse, request.EndGetResponse, null);

    Console.WriteLine(msg + " status code: " + response.StatusCode);
    Console.WriteLine(msg + " end");

    response.Dispose(); 
}

Вывод

0 begin
1 begin
2 begin
3 begin
4 begin
5 begin
6 begin
7 begin
8 begin
9 begin
3 status code: OK
3 end
5 status code: OK
5 end
0 status code: OK
0 end
6 status code: OK
6 end
2 status code: OK
2 end
7 status code: OK
7 end
1 status code: OK
1 end
8 status code: OK
8 end
9 status code: OK
9 end
4 status code: OK
4 end   

UPD

Не забываем диспозить респонс

    static async Task WR(int msg)
    {
        Console.WriteLine(msg + " begin");

        string url = "https://stackoverflow.com";
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "GET";

        using (var response = (HttpWebResponse)
            await Task.Factory
            .FromAsync(request.BeginGetResponse, request.EndGetResponse, null)) //// <<<<<
        {
            Console.WriteLine(msg + " status code: " + response.StatusCode);
            Console.WriteLine(msg + " end");
        }
    }