[Flutter] Flutter Bloc Problem with timeout on stream listening

I'm using Bloc library in my Flutter application.

On processing some event I'm listening stream and want to handle timeout.

This is code example:

await emit.onEach(
bluetoothConnection.input!,
onData: (data) {
answer = answer + String.fromCharCodes(data);
if (answer.contains('hellok')) {
isAnswered = true;
emit(
ConnectionSuccessState(
device: event.device.copyWith(
isConnected: true,
bluetoothConnection: bluetoothConnection,
),
),
);
}
},
).timeout(const Duration(seconds: 1), onTimeout: () {
debugPrint('onTimeout');
});


When timeout occur I see debug record

I/flutter ( 5875): onTimeout


And then I got exception like this

E/flutter ( 5875): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 'package:bloc/src/emitter.dart': Failed assertion: line 150 pos 7: '_disposables.isEmpty':
E/flutter ( 5875):
E/flutter ( 5875): An event handler completed but left pending subscriptions behind.
E/flutter ( 5875): This is most likely due to an unawaited emit.forEach or emit.onEach.
E/flutter ( 5875): Please make sure to await all asynchronous operations within event handlers.
E/flutter ( 5875):
E/flutter ( 5875): **BAD**
E/flutter ( 5875): on<Event>((event, emit) {
E/flutter ( 5875): emit.forEach(...);
E/flutter ( 5875): });
E/flutter ( 5875):
E/flutter ( 5875): **GOOD**
E/flutter ( 5875): on<Event>((event, emit) async {
E/flutter ( 5875): await emit.forEach(...);
E/flutter ( 5875): });


What the right way to process timeout in my stream listening?

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