SpanProcessesInTasks.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            var cts = new CancellationTokenSource();
            var ct = cts.Token;



            var tasks = new List<Task>();

            Action bumm = () =>
            {
                var process = Process.Start(@"c:\Windows\System32\cmd.exe", "/k");

                if (process == null) throw new NotSupportedException();

                while (true)
                {
                    if (ct.WaitHandle.WaitOne(TimeSpan.FromSeconds(1)))
                    {
                        process.Kill();

                        return;
                    }
                }
            };

            var t = new Task(bumm, ct);
            t.Start();
            tasks.Add(t);


            tasks.Add(Task.Factory.StartNew(bumm, ct));

            try
            {
                Console.ReadKey();

                cts.Cancel();

                Task.WaitAll(tasks.ToArray());
            }
            catch (AggregateException ae)
            {
                foreach (Exception e in ae.InnerExceptions)
                    Console.Error.WriteLine(e.Message);
            }
        }
    }
}