在User构造函数上，需要使用const才能在StartOnboarding上使用const

class StartOnboarding extends OnboardingEvent {
  final User user;

  const StartOnboarding({
    this.user = const User(
      id: '',
      name: '',
      age: 0,
      gender: '',
      imageUrls: [],
    ),
  });

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

class User {
  final String id;
  final String name;
  final int age;

  final String gender;
  final List<String> imageUrls;
 const  User({
    required this.id,
    required this.name,
    required this.age,
    required this.gender,
    required this.imageUrls,
  });
}