No Element Bad State when dismiss flush bar

[chantip-pi]

Describe the bug
I found this bug in datadog and from the error message I assume it occur when the user try to load a page after an app bar i shown and something went wrong with the navigation logic
I use a custom flush bar for my app which extends from the flush bar from this library and i override the field show

   @override
  Future show(BuildContext context) {
    if (currentHash != context.hashCode) {
      currentHash = context.hashCode;
      return super.show(context).then((_) => currentHash = null);
    }
    return Future.value(null);
  }

I did check content.mounted before showing flush bar

To Reproduce
Currently I am not sure if I found the root cause so I am unable to reproduce this error

Smartphone

• Device: Android
• Version 11, 15

Bad state: No element
#0 Iterable.firstWhere (third_party/dart/sdk/lib/core/iterable.dart:704)
#1 NavigatorState.removeRoute (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/widgets/navigator.dart:5652)
#2 FlushbarRoute._getDismissibleFlushbar.<anonymous closure> (/Users/vagrant/.pub-cache/hosted/pub.dev/another_flushbar-1.12.30/lib/flushbar_route.dart:191)
#3 _DismissibleState._startResizeAnimation (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/widgets/dismissible.dart:585)
#4 _DismissibleState._handleMoveCompleted (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/widgets/dismissible.dart:558)
#0 StackZoneSpecification._currentTrace (/Users/vagrant/.pub-cache/hosted/pub.dev/stack_trace-1.12.1/lib/src/stack_zone_specification.dart:222)
#1 StackZoneSpecification._createNode (/Users/vagrant/.pub-cache/hosted/pub.dev/stack_trace-1.12.1/lib/src/stack_zone_specification.dart:195)
#2 StackZoneSpecification._registerBinaryCallback (/Users/vagrant/.pub-cache/hosted/pub.dev/stack_trace-1.12.1/lib/src/stack_zone_specification.dart:136)
#3 StackZoneSpecification._registerBinaryCallback (/Users/vagrant/.pub-cache/hosted/pub.dev/stack_trace-1.12.1/lib/src/stack_zone_specification.dart:132)
#4 _CustomZone.registerBinaryCallback (third_party/dart/sdk/lib/async/zone.dart:1459)
#4 _SuspendState._createAsyncCallbacks (third_party/dart/sdk/lib/_internal/vm/lib/async_patch.dart:231)
#5 _SuspendState._await (third_party/dart/sdk/lib/_internal/vm/lib/async_patch.dart:315)
#6 _DismissibleState._handleDismissStatusChanged (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/widgets/dismissible.dart:543)
#7 _DismissibleState._handleDismissStatusChanged (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/widgets/dismissible.dart:541)
#8 AnimationLocalStatusListenersMixin.notifyStatusListeners (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/animation/listener_helpers.dart:243)
#9 AnimationController._checkStatusChanged (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/animation/animation_controller.dart:964)
#10 AnimationController._tick (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/animation/animation_controller.dart:982)
#11 AnimationController._tick (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/animation/animation_controller.dart:968)
#12 Ticker._tick (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/ticker.dart:277)
#13 Ticker._tick (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/ticker.dart:271)
#14 SchedulerBinding._invokeFrameCallback (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/binding.dart:1442)
#15 SchedulerBinding.handleBeginFrame.<anonymous closure> (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/binding.dart:1273)
#16 _LinkedHashMapMixin.forEach (third_party/dart/sdk/lib/_internal/vm_shared/lib/compact_hash.dart:763)
#17 SchedulerBinding.handleBeginFrame (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/binding.dart:1271)
#18 SchedulerBinding._handleBeginFrame (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/binding.dart:1187)
#19 SchedulerBinding._handleBeginFrame (/Users/vagrant/fvm/versions/3.29.2/packages/flutter/lib/src/scheduler/binding.dart:1178)
#20 _rootRunUnary (third_party/dart/sdk/lib/async/zone.dart:1546)
#21 _rootRunUnary (third_party/dart/sdk/lib/async/zone.dart:1531)
#22 _CustomZone.runUnary (third_party/dart/sdk/lib/async/zone.dart:1429)
#23 _CustomZone.runUnaryGuarded (third_party/dart/sdk/lib/async/zone.dart:1329)
#24 _invoke1 (lib/ui/hooks.dart:334)
#25 PlatformDispatcher._beginFrame (lib/ui/platform_dispatcher.dart:410)
#26 _beginFrame (lib/ui/hooks.dart:277)
#27 _beginFrame (lib/ui/hooks.dart:275)