Router crashed if RouteInformation.state is not a string #87823
Description
Runs the book_store example of https://github.com/tomgilder/routemaster/tree/main/example will cause the crash
Error: Expected a value of type 'String?', but got one of type '_JsonMap'
at Object.throw_ [as throw] (http://localhost:62458/dart_sdk.js:5087:11)
at Object.castError (http://localhost:62458/dart_sdk.js:5046:15)
at Object.cast [as as] (http://localhost:62458/dart_sdk.js:5371:17)
at dart.NullableType.new.as (http://localhost:62458/dart_sdk.js:6874:60)
at Object.JsonExtensions$124tryString [as JsonExtensions|tryString] (http://localhost:62458/dart_sdk.js:181075:25)
at _engine.EngineSingletonFlutterWindow.new.<anonymous> (http://localhost:62458/dart_sdk.js:176611:168)
at Generator.next (<anonymous>)
at runBody (http://localhost:62458/dart_sdk.js:38671:34)
at Object._async [as async] (http://localhost:62458/dart_sdk.js:38702:7)
at http://localhost:62458/dart_sdk.js:176586:57
at _engine.EngineSingletonFlutterWindow.new._waitInTheLine (http://localhost:62458/dart_sdk.js:176577:27)
at _waitInTheLine.next (<anonymous>)
at http://localhost:62458/dart_sdk.js:38652:33
at _RootZone.runUnary (http://localhost:62458/dart_sdk.js:38523:59)
at _FutureListener.thenAwait.handleValue (http://localhost:62458/dart_sdk.js:33725:29)
at handleValueCallback (http://localhost:62458/dart_sdk.js:34277:49)
at Function._propagateToListeners (http://localhost:62458/dart_sdk.js:34315:17)
at _Future.new.[_completeWithValue] (http://localhost:62458/dart_sdk.js:34163:23)
at async._AsyncCallbackEntry.new.callback (http://localhost:62458/dart_sdk.js:34184:35)
at Object._microtaskLoop (http://localhost:62458/dart_sdk.js:38790:13)
at _startMicrotaskLoop (http://localhost:62458/dart_sdk.js:38796:13)
at http://localhost:62458/dart_sdk.js:34531:9