IStateObservableEx to discuss

IStateObservableEx.dart

import 'package:bloc/bloc.dart';

extension IStateObservableEx<State extends Object?> on IStateObservable<State> {
  StateObservable<SubState> whereState<SubState extends State>() => StateObservable<SubState>(
        (state is SubState ? state : null) as SubState,
        stream.whereState<SubState>(),
      );
}

class StateObservable<State extends Object?> {
  final State _state;
  final Stream<State> _stream;

  StateObservable(this._state, this._stream);

  State get state => _state;

  Stream<State> get stream => _stream;
}