streamController_bug_question.dart

import 'dart:async';

void main() {
  // failure
  final t1 = State1();
  t1._stateBroadcaster.add(true);
  //works fine
  final t2 = State2();
  t2._stateBroadcaster.add(true);
}

class State1 {
  StreamController _stateBroadcaster;

  State1() {
    _stateBroadcaster = StreamController.broadcast(
        onCancel: _stateBroadcaster.close);
  }
}

class State2 {
  StreamController _stateBroadcaster;

  State2() {
    _stateBroadcaster = StreamController.broadcast(
        onCancel: () {
          _stateBroadcaster.close();
        });
  }
}