document withoutObjectCaching

eloquent-mutators.md

@@ -91,6 +91,36 @@ public function address(): Attribute
 }
 ```
 
+When returning value objects from accessors, any changes made to the value object will automatically be synced back to the model before the model is saved. This is possible because Eloquent retains instances returned by accessors so it can be return the same instance each time the accessor is invoked:
+
+    use App\Models\User;
+
+    $user = User::find(1);
+
+    $user->address->lineOne = 'Updated Address Line 1 Value';
+    $user->address->lineTwo = 'Updated Address Line 2 Value';
+
+    $user->save();
+
+If you would like to disable the object caching behavior of attributes, you may invoke the `withoutObjectCaching` method when defining the attribute:
+
+```php
+/**
+ * Interact with the user's address.
+ *
+ * @return  \Illuminate\Database\Eloquent\Casts\Attribute
+ */
+public function address(): Attribute
+{
+    return (new Attribute(
+        get: fn ($value, $attributes) => new Address(
+            $attributes['address_line_one'],
+            $attributes['address_line_two'],
+        ),
+    ))->withoutObjectCaching();
+}
+```
+
 <a name="defining-a-mutator"></a>
 ### Defining A Mutator