Type Alias PostRootBuilder 

pub type PostRootBuilder = Box<dyn FnOnce(&mut WidgetTree, WidgetId) -> WidgetId>;

Per-window post-root hook. Runs after the user’s root_builder returns, with the resulting WidgetId. The hook may wrap the user root in another widget and return the wrapper’s id, or simply return the original id unchanged. Used by the debug inspector to splice an inspector shell around every window’s root in debug builds.

Aliased Type

pub struct PostRootBuilder(/* private fields */);