优化

render_2D/render_2D/scene/Render_Scene_2D.ipp

@@ -328,6 +328,10 @@ void Render_Scene_2D::Private::ensure_frame_taskflow(Object* object) {
 template <Attached Object>
 std::expected<void, Render_Scene_2D::Render_Result>
 Render_Scene_2D::Private::render(Object* object, Frame_2D* frame) {
+    if (!frame)
+        throw std::invalid_argument(
+            "Render_Scene_2D requires a non-null external frame");
+    frame->mark(Frame_Trace_Marker::scene_render_entered);
     Frame_Callback callback;
     Frame_Callback retired_callback;
     {
@@ -353,7 +357,9 @@ Render_Scene_2D::Private::render(Object* object, Frame_2D* frame) {
          * no Taskflow is running.  The completion callback only publishes
          * results; it must not modify a graph that is still executing.
          */
+        frame->mark(Frame_Trace_Marker::scene_advance_started);
         double_buffer::detail::Internal_Access::advance(object);
+        frame->mark(Frame_Trace_Marker::scene_advance_finished);
         const Prop& prop = double_buffer::detail::Internal_Access::current_prop_layer<Render_Scene_2D::Base_Tag>(object);
         if (!prop.view_active) {
             release_admission();