面試八股文：你寫過自定義任務(wù)調(diào)度器嗎？

/// <summary>/// Schedules a task to the ThreadPool./// </summary>/// <param name="task">The task to schedule.</param>protected internal override void QueueTask(Task task){     TaskCreationOptions options = task.Options;     if ((options & TaskCreationOptions.LongRunning) != 0)     {          // Run LongRunning tasks on their own dedicated thread.          Thread thread = new Thread(s_longRunningThreadWork);          thread.IsBackground = true; // Keep this thread from blocking process shutdown          thread.Start(task);    }    else    {         // Normal handling for non-LongRunning tasks.        bool preferLocal = ((options & TaskCreationOptions.PreferFairness) == 0);        ThreadPool.UnsafeQueueUserWorkItemInternal(task, preferLocal);    }}

public sealed class CustomTaskScheduler : TaskScheduler, IDisposable    {        private BlockingCollection<Task> tasksCollection = new BlockingCollection<Task>();        private readonly Thread mainThread = null;        public CustomTaskScheduler()        {            mainThread = new Thread(new ThreadStart(Execute));            if (!mainThread.IsAlive)            {                mainThread.Start();            }        }        private void Execute()        {            foreach (var task in tasksCollection.GetConsumingEnumerable())            {                TryExecuteTask(task);            }        }        protected override IEnumerable<Task> GetScheduledTasks()        {            return tasksCollection.ToArray();        }        protected override void QueueTask(Task task)        {            if (task != null)                tasksCollection.Add(task);                   }        protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)        {            return false;        }        private void Dispose(bool disposing)        {            if (!disposing) return;            tasksCollection.CompleteAdding();            tasksCollection.Dispose();        }        public void Dispose()        {            Dispose(true);            GC.SuppressFinalize(this);        }    }