primaryNavigation property
The slot placed on the beginning side of the app window.
The beginning side means the right when the ambient Directionality is TextDirection.rtl and on the left when it is TextDirection.ltr.
If the content is a flexibly sized Widget like Container, wrap the content in a SizedBox or limit its size (width and height) by another method. See the builder in AdaptiveScaffold.standardNavigationRail for an example.
Implementation
final SlotLayout? primaryNavigation;