TaskContinuationOptions.OnlyOnCancelled创建取消

exception details: A task was canceled.

只是在想为什么要加 TaskContinuationOptions.OnlyOnCanceled OnlyOnCanceled 创建取消?

 class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("starting");
            Task<int> t = Task.Run(() => 42)
                .ContinueWith((i) =>
                {
                    Console.WriteLine("Canceled");
                    return i.Result * 2;
                }, TaskContinuationOptions.OnlyOnCanceled);




            Console.WriteLine("ending");

            try
            {

                Console.WriteLine("ret {0}", t.Result);
            }
            catch (AggregateException ae)
            {
                ae.Handle(ex => { Console.WriteLine("exception details: {0}",ex.Message);
                    return true;
                });
            }

            Console.ReadLine();



        }