Flutter bloc pattern

I'm learning bloc pattern. I could not understand what is the usecase of this toString function in bloc pattern. Ok I did convert the constructor to string and passed it the counter, so what?! why should I even do something like that?!

class CounterState extends Equatable {
  final int counter;

  const CounterState({
    required this.counter,
  });

  factory CounterState.initial() {
    return const CounterState(counter: 0);
  }

  // THIS FUNCTION 
  @override
  String toString() => 'CounterState(counter: $counter)';
  //

  CounterState copyWith({
    int? counter,
  }) {
    return CounterState(
      counter: counter ?? this.counter,
    );
  }

  @override
  List<Object> get props => [counter];
}