async_concurrency.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace ThreadAsyncTest
{
    class Program
    {
        static async Task DoSomething(int taskId)
        {
            await Task.Delay(0);
            var counter = 0;
            while (counter < 10)
            {
                Console.WriteLine($"Task {taskId} - Thread id {Thread.CurrentThread.ManagedThreadId} - count {counter++}");
                Thread.Sleep(100);
            }

            Console.WriteLine($"Task {taskId} finished.");

        }
        static async Task Main(string[] args)
        {
            Console.WriteLine($"Program starts - Thread id {Thread.CurrentThread.ManagedThreadId}");

            var task1 = DoSomething(1);
            var task2 = DoSomething(2);

            await Task.WhenAll(task1, task2);

            Console.WriteLine($"Program ends - Thread id {Thread.CurrentThread.ManagedThreadId}");

            Console.ReadKey();
        }
    }
}