using System;

using System.Net.Http;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main(string[] args)

    {

        var task1 = Foo(1);

        var task2 = Foo(2);

        var task3 = Foo(3);

​

        Thread.Sleep(TimeSpan.FromSeconds(3));

        Console.WriteLine("Main");

​

        await task1;

        await task2;

        await task3;

    }

​

    private static async Task Foo(int taskNum)

    {

        using var httpClient = new HttpClient();

        var result = await httpClient.GetAsync("https://yandex.ru");

        Console.WriteLine($"{taskNum} {result.StatusCode}");

    }

}