game version overlay, working on actors sync

Editor/Background/EnsureUniqueActorID.cs

@@ -0,0 +1,34 @@
+using RebootKit.Engine.Foundation;
+using RebootKit.Engine.Simulation;
+using UnityEditor;
+using UnityEngine;
+
+namespace RebootKit.Editor.Background {
+    [InitializeOnLoad]
+    public class EnsureUniqueActorID {
+        static EnsureUniqueActorID() {
+            ObjectChangeEvents.changesPublished += OnObjectChange;
+        }
+
+        static void OnObjectChange(ref ObjectChangeEventStream stream) {
+
+            for (int i = 0; i < stream.length; ++i) {
+                switch (stream.GetEventType(i)) {
+                    case ObjectChangeKind.CreateGameObjectHierarchy:
+                        stream.GetCreateGameObjectHierarchyEvent(i, out CreateGameObjectHierarchyEventArgs createEvent);
+
+                        GameObject gameObjectChanged =
+                            EditorUtility.InstanceIDToObject(createEvent.instanceId) as GameObject;
+
+                        if (gameObjectChanged != null && gameObjectChanged.TryGetComponent(out Actor actor)) {
+                            actor.ActorID = UniqueID.NewULongFromGuid();
+                            EditorUtility.SetDirty(actor);
+                        }
+
+                        break;
+                }
+            }
+            
+        }
+    }
+}