The DevTools can't not show correct frame histogram and also SchedulerBinding.instance.addTimingsCallback report is not correct when auto frame = surface_->AcquireFrame(layer_tree.frame_size()); takes much time.

But Android studio intellj plugin can show correct things(When AS plugin show red frames, I can see the junk visually).

See also:

• Constant Animation Jank in Simple Flutter App #103847 (comment)
• Constant Animation Jank in Simple Flutter App #103847 (comment)
• Performance on iPhone XS / iPhone XR significantly low (~20fps instead of 60fps) #115036 (comment)

About why this operation will be time-consuming, see my PR below (Still WIP & Needs triage)

• [WIP][iOS] Avoid nextDrawable take much time. engine#38551