Controls the transfer of focus beyond the first and the last items of a focus scope that defines focus traversal of widgets within a route.
The focus inside routes installed in the top of the app affects how
the app behaves with respect to the platform content surrounding it.
For example, on the web, an app is at a minimum surrounded by browser UI,
such as the address bar, browser tabs, and more. The user should be able
to reach browser UI using normal focus shortcuts. Similarly, if the app
is embedded within an
<iframe> or inside a custom element, it should
be able to participate in the overall focus traversal, including elements
not rendered by Flutter.
final TraversalEdgeBehavior routeTraversalEdgeBehavior;