C#下一个简单的Actor模型实现

网上关于Actor的内容有很多，这里提供一种简单的实现。直接上码：

public abstract class Actor<T>
{
        public static readonly int StateWaiting = 0;
        public static readonly int StateExecuting = 1;
        public static readonly int StateExit = 2;

        private readonly Queue<T> _messages;
        private volatile int _status;

        public bool IsBusy => _status == StateExecuting;

        protected Actor()
        {
            _messages = new Queue<T>();
        }

        public void Receive(T message)
        {
            if (IsValid(message))
            {
                lock (_messages)
                {
                    _messages.Enqueue(message);
                }

                StartHandleMessage();
            }
        }

        protected abstract bool IsValid(T message);

        private void StartHandleMessage()
        {
            if (Interlocked.CompareExchange(ref _status, StateExecuting, StateWaiting) == StateWaiting)
            {
                var msg = _messages.Dequeue();
                ThreadPool.QueueUserWorkItem(DoHandleMessage, msg);
            }
        }

        private void DoHandleMessage(object message)
        {
            if (_status != StateExit)
            {
                HandleMessageImpl((T)message);

                if (_messages.Count > 0)
                {
                    var msg = _messages.Dequeue();
                    DoHandleMessage(msg);
                }
                else
                {
                    _status = StateWaiting;
                }
            }
        }

        protected abstract void HandleMessageImpl(T message);

        public void Exit()
        {
            _status = StateExit;
        }
    }
}