public class PCQueue
    {
        readonly object _locker = new object();
        Thread[] _workers;
        Queue<Action> _itemQ = new Queue<Action>();

        public PCQueue(int workerCount)
        {
            _workers = new Thread[workerCount];
            for (int i = 0; i < workerCount; i++)
                (_workers[i] = new Thread(Consume)).Start();
        }

        public void Shutdown()
        {
            for (int i = 0; i < _workers.Length; i++)
            {
               lock (_locker)
                {
                    _itemQ.Enqueue(null);           
                    Monitor.Pulse(_locker);          
                } 
            }
                

        }

        public void QueueWorkItem<T>(Action<T> action, T arg)
        {
            lock (_locker)
            {
                _itemQ.Enqueue(()=>action(arg));           
                Monitor.Pulse(_locker);         
            }
        }

        void Consume()
        {
            while (true)                       
            {                                   
                Action item;
                lock (_locker)
                {
                    while (_itemQ.Count == 0) Monitor.Wait(_locker);
                    item = _itemQ.Dequeue();
                }
                if (item == null) return;         
                item();                          
            }
        }
    }