Dart's factory singleton

main.dart

void main(List<String> arguments) {
  var a1 = Storage();
  var a2 = Storage();
  print(a1.hashCode);
  print(a2.hashCode);
  print(a1==a2);
}

class Storage {
  static final Storage _singleton = Storage._internal();
  factory Storage() => _singleton;

  Storage._internal(){
    print('initialize code here...');
  }
}