Lazy initialization in dart

lazy_init.dart

void main() {
  print("entry point");

  print(string);
  print(string);
  print(customClass);
  print(customClass);

  print("exit point");
}

String string = () {
  print("It initialises only once");
  return "Lorem ipsum";
}();

CustomClass customClass = () {
  print("It initialises object only once");
  return CustomClass();
}();

class CustomClass {
  CustomClass() {
    print("CustomClass constructor called");
  }
  @override
  String toString() => "CustomClass";
}