using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    private static readonly TimeSpan _period = TimeSpan.FromMilliseconds(500);

    private static readonly CancellationTokenSource _stopper = new CancellationTokenSource();

    private static int _x = 1;

    public static async Task Main()

    {

        try

        {

            var stoppingToken = _stopper.Token;

            using PeriodicTimer timer = new(_period);

​

            while (!stoppingToken.IsCancellationRequested && await timer.WaitForNextTickAsync(stoppingToken))

            {

                await DoWork();

            }       

        }

        finally

        {

            _stopper.Dispose();

        }

    }

    private static ValueTask DoWork()

    {

        Console.WriteLine($"{_x}:{DateTimeOffset.Now:mm:ss.ffff}"); 

        if (_x == 9)

        {

            _stopper.Cancel();

        }

        else

        {

            _x += 1;

        }

        return ValueTask.CompletedTask;

    }

}