如何使用built_value和StandardJsonPlugin序列化多态对象列表？

dependencies:
  built_value: ^7.1.0
  built_collection: ^4.3.0

import 'package:built_collection/built_collection.dart';
import 'package:built_value/built_value.dart';

part 'animal_list.g.dart';

abstract class AnimalList implements Built<AnimalList, AnimalListBuilder> {
  BuiltList<Animal> get animals;

  AnimalList._();
  factory AnimalList([void Function(AnimalListBuilder) updates]) = _$AnimalList;
}

import 'package:built_value/built_value.dart';

part 'animal.g.dart';

abstract class Animal implements Built<Animal, AnimalBuilder> {
  String get name;

  Animal._();
  factory Animal([void Function(AnimalBuilder) updates]) = _$Animal;
}

flutter packages pub run build_runner build

import 'package:built_value/serializer.dart';
import 'package:built_value/standard_json_plugin.dart';

void main() {
  // 注册StandardJsonPlugin插件
  final standardSerializers = (serializers.toBuilder()
    ..addPlugin(StandardJsonPlugin())).build();

  // 序列化AnimalList对象
  final animalList = AnimalList((b) => b
    ..animals = ListBuilder<Animal>([
      Cat((b) => b..name = 'Tom'),
      Dog((b) => b..name = 'Max'),
    ]));

  final json = standardSerializers.serialize(animalList);
  final jsonString = jsonEncode(json);

  print(jsonString);

  // 反序列化AnimalList对象
  final parsedJson = jsonDecode(jsonString);
  final deserializedAnimalList = standardSerializers.deserialize(parsedJson);

  print(deserializedAnimalList);
}