flutter - 如何创建具有私有可为空属性的冻结类

Question

我有一个像这样的普通班

enum FamilyRelationEnum { father, mother, brother, sister }

class FamilyMemberResponse {
  FamilyMemberResponse(this.name, this.relation);

  final String name, relation;
  FamilyRelationEnum? _relationEnum;

  FamilyRelationEnum get relationEnum => _relationEnum ??=
      FamilyRelationEnum.values.firstWhere((e) => e.name == relation);
}

我只想生成它的冻结版本。这是我到目前为止所尝试的......

@freezed
class FreezedFamilyMemberResponse with _$FreezedFamilyMemberResponse {
  const FreezedFamilyMemberResponse._();

  const factory FreezedFamilyMemberResponse(String? name, String? relation) =
      _FreezedFamilyMemberResponse;

  factory FreezedFamilyMemberResponse.fromJson(Map<String, dynamic> json) =>
      _$FreezedFamilyMemberResponseFromJson(json);

  FamilyRelationEnum? _relationEnum;

  FamilyRelationEnum get relationEnum => _relationEnum ??=
      FamilyRelationEnum.values.firstWhere((e) => e.name == relation);
}

由于非 final 字段，无法完成代码生成。或者有没有更好的解决方案来在构建时映射枚举。提前致谢 ：）