class Program
    {
        static async Task Main(string[] args)
        {
            var cts = new CancellationTokenSource();
            var task = DoSomeWork(cts.Token);
            await Task.Delay(2000);
            cts.Cancel();
            await Task.Delay(2000);
            WriteLine("Yep, we done");
            ReadLine();
        }

        private async static Task DoSomeWork(CancellationToken token)
        {
            try
            {
                while(true)
                {
                    await Task.Delay(1000);
                    token.ThrowIfCancellationRequested();
                }
            }
            catch(OperationCanceledException)
            {
                WriteLine("Task cancelled!");
            }
            catch(Exception)
            {
                WriteLine("wth?");
            }

        }
    }