detach

Clear widgets without triggering an update the displayed UI.

After this is called there will be no further calls to insert, remove, or move widgets, and no further updates to widgets' modifiers.

Implementations must clear all direct references to Widget instances. This is necessary because widget implementations may be reference-counted (as in Swift) and may also contain references to Kotlin objects to create a retain cycle. We require implementations of this class to be where this cycle is broken because it's a non-invasive place to do so.

This function is not recursive.