4.3	序列化 Serialization
1.	总是标记未封装的类为[Serializable]
Always mark non-sealed classes as serializable.
2.	总是标记未序列化的成员变量为[non-serializable]
Always mark un-serializable member variables as non-serializable.
3.	总是标记序列化类中的委托为[NonSerialized]
Always mark delegates on a serialized class as non- serializable fields.
[Serializable]
public class MyClass
{
   [field: NonSerialized]
   public event EventHandler MyEvent;
}