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：

 1 public abstract class Actor<T>
 2 {
 3         public static readonly int StateWaiting = 0;
 4         public static readonly int StateExecuting = 1;
 5         public static readonly int StateExit = 2;
 6 
 7         private readonly Queue<T> _messages;
 8         private volatile int _status;
 9 
10         public bool IsBusy => _status == StateExecuting;
11 
12         protected Actor()
13         {
14             _messages = new Queue<T>();
15         }
16 
17         public void Receive(T message)
18         {
19             if (IsValid(message))
20             {
21                 lock (_messages)
22                 {
23                     _messages.Enqueue(message);
24                 }
25 
26                 StartHandleMessage();
27             }
28         }
29 
30         protected abstract bool IsValid(T message);
31 
32         private void StartHandleMessage()
33         {
34             if (Interlocked.CompareExchange(ref _status, StateExecuting, StateWaiting) == StateWaiting)
35             {
36                 var msg = _messages.Dequeue();
37                 ThreadPool.QueueUserWorkItem(DoHandleMessage, msg);
38             }
39         }
40 
41         private void DoHandleMessage(object message)
42         {
43             if (_status != StateExit)
44             {
45                 HandleMessageImpl((T)message);
46 
47                 if (_messages.Count > 0)
48                 {
49                     var msg = _messages.Dequeue();
50                     DoHandleMessage(msg);
51                 }
52                 else
53                 {
54                     _status = StateWaiting;
55                 }
56             }
57         }
58 
59         protected abstract void HandleMessageImpl(T message);
60 
61         public void Exit()
62         {
63             _status = StateExit;
64         }
65     }
66 }