Task t1 = new Task(MyMethod);

Task t1 = Task.Factory.StartNew(MyMethod);

  /// <summary>
  ///做事 需要 ms秒 才能完成
  /// </summary>
  /// <param name="time"></param>
  /// <returns></returns>
  static async Task<string> Doing(int time, string name = "我")
  {
   Console.WriteLine(name+"来了");
   await Task.Delay(TimeSpan.FromMilliseconds(time));
   return string.Format("这活{1}干了：{0}ms ", time,name);
  }
  /// <summary>
  /// 设定超时任务 如果超时返回
  /// </summary>
  /// <param name="needTimeOut"></param>
  /// <returns></returns>
  static async Task<string> TimeOut(bool needTimeOut)
  {
   Console.WriteLine(needTimeOut);
   var t=new Stopwatch();
   t.Start();
   var timeOutTask = Task.Delay(150);//1.设定一个超时的任务
   var doing = Doing(needTimeOut ? 100 : 300);//2. 真正需要执行的任务
   var task = await Task.WhenAny(doing,timeOutTask);//返回任何一个完成的任务
   if (task == timeOutTask)//如果超时任务先完成了 就返回 很可惜 他没有完成！
   {
    return "很可惜 他没有完成！";
   }
   t.Stop();
   Console.WriteLine("耗时："+t.Elapsed.TotalMilliseconds);
   return await doing;
  }
  /// <summary>
  /// 多任务一起执行
  /// </summary>
  /// <returns></returns>
  static async Task Tasks()
  {
   var t = new Stopwatch();
   t.Start();
   var list=new List<string>();
   var t1 = Doing(1000, "1000");//1.定义任务
   var t2 = Doing(1500, "1500");
   var t3 = Doing(1200, "1200");
   var tasks = new[] {t1, t2, t3};//2.任务组
   var process = tasks.Select(async tt =>//3.等待任务结束 并保存值
   {
    var result = await tt; 
    list.Add(result);
   });
   await Task.WhenAll(process);//4.等待处理完全
   foreach (var i in list)//5.查看结果
   {
    Console.WriteLine(i);
   }
   t.Stop();
   Console.WriteLine("耗时：" + t.Elapsed.TotalMilliseconds);   
  }