relation error ValueStream has no value.

main.dart

import 'package:flutter/material.dart';
import 'package:relation/relation.dart';
import 'package:rxdart/rxdart.dart';

void main() {
  runApp(MyHomePage());
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late StreamedState<bool> streamedState;
  final BehaviorSubject<bool> subj = BehaviorSubject.seeded(true);

  @override
  void initState() {
    super.initState();
    streamedState = StreamedState.from(subj.stream);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: StreamedStateBuilder<bool>(
            streamedState: streamedState,
            builder: (context, val) => Text('$val'),
          ),
        ),
      ),
    );
  }
}