结构大修改，改成朴实无华的结构，不过度架构。能跑就行

Assets/Scripts/NBC/Asset/Runtime/Tasks/Unpack/UnpackVersionTask.cs

@@ -0,0 +1,40 @@
+using System.IO;
+
+namespace NBC.Asset
+{
+    public class UnpackVersionTask : NTask
+    {
+        private readonly bool _download;
+        private readonly string _savePath;
+        private UnpackFileTask _unpackFileTask;
+
+        public UnpackVersionTask(bool download = false)
+        {
+            _savePath = Const.GetCachePath(Const.VersionFileName);
+            _download = download;
+        }
+
+        protected override void OnStart()
+        {
+            if (File.Exists(_savePath))
+            {
+                Finish();
+            }
+            else
+            {
+                _unpackFileTask = new UnpackFileTask(Const.VersionFileName, _download);
+                _unpackFileTask.Run(TaskRunner.Def);
+            }
+        }
+
+        protected override NTaskStatus OnProcess()
+        {
+            if (_unpackFileTask != null)
+            {
+                return _unpackFileTask.Status;
+            }
+
+            return NTaskStatus.Success;
+        }
+    }
+}