ProtoObject改成抽象类，不能实例化

Unity/Assets/ThirdParty/Unity.ThirdParty.asmdef

@@ -1,5 +1,6 @@
 {
     "name": "Unity.ThirdParty",
+    "rootNamespace": "",
     "references": [],
     "includePlatforms": [],
     "excludePlatforms": [],

Unity/Codes/Model/Core/Object/ProtoObject.cs

@@ -18,7 +18,7 @@ namespace ET
     }
 #endif
     
-    public class ProtoObject: Object, ISupportInitialize
+    public abstract class ProtoObject: Object, ISupportInitialize
     {
         public object Clone()
         {