fix: Optimized the Type property setter

When TypeReference was created or its Type property was set through scripting, it took 80ms because GUID was searched for each time. Now, GUID search has moved to OnBeforeSerialize(), so TypeReference creation/change takes less than 1 ms.

Author: SolidAlloy

Runtime/TypeReference.cs

@@ -29,6 +29,7 @@ public class TypeReference : ISerializationCallbackReceiver
         private Type _type;
 
         private bool _needToLogTypeNotFound;
+        private bool _typeChanged;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="TypeReference"/> class with Type equal to null.
@@ -87,9 +88,11 @@ public Type Type
             {
                 MakeSureTypeHasName(value);
 
+                if (_type != value)
+                    _typeChanged = true;
+
                 _type = value;
                 TypeNameAndAssembly = GetTypeNameAndAssembly(value);
-                SetClassGuidIfExists(value);
             }
         }
 
@@ -110,6 +113,12 @@ void ISerializationCallbackReceiver.OnAfterDeserialize()
 
         void ISerializationCallbackReceiver.OnBeforeSerialize()
         {
+            if (_typeChanged)
+            {
+                SetClassGuidIfExists(Type);
+                _typeChanged = false;
+            }
+
 #if UNITY_EDITOR
             EditorApplication.delayCall -= TryUpdatingTypeUsingGUID;
             EditorApplication.delayCall -= LogTypeNotFoundIfNeeded;
@@ -223,6 +232,7 @@ private void SetClassGuidIfExists(Type type)
             }
             catch (UnityException) // thrown on assembly recompiling if field initialization is used on field.
             {
+                // GUID will be found in SerializedTypeReference.SetGuidIfAssignmentFailed()
                 GuidAssignmentFailed = true;
                 GUID = string.Empty;
             }