[go_router] Support asynchronous redirects #105808
Description
This is a proposal to change GoRouterRedirect to an asynchronous function.
typedef GoRouterRedirect = Future<String?> Function(GoRouterState state);This would allow a redirect to make asynchronous calls, for example to check if the user is signed in:
redirect: (state) async {
final signedIn = await _appState.auth.isSignedIn();
if (!signedIn) return '/signin';
return null;
},