Pre calculate UI size

Hi there,

is it possible to precompute the size of a layout control in Unity UI?

Example:

I have a VerticalLayoutGroup with 4 buttons inside. I want to know how much space the vertical Layoutgroup needs if I would add another button (or any other control).

I tried to add the 5. button, call LayoutRebuilder.ForceRebuildLayoutImmediate() and remove the button again. But the preferred...

Pre calculate UI size