How to get screen position of a RectTransform when canvas render mode set to "Screen Space - Overlay"

Questions & Answers
1

I can get a camera and do thing like camera.WorldToScreenPoint to get screen position of a RectTransform
when setting Canvas’ render mode to “Screen Space - Camera” or “World Space”.
But when I set render mode to “Screen Space - Overlay”, there is no camera rendering this canvas,
how can I get screen position of a RectTransform?

2

I finally found that just use RectTransformUtility.WorldToScreenPoint and pass Camera as null…
Or just use that world position if you are using Screen Space - Overlay mode.