How to remove the `__typename` in the `toJson` of a fragment about ferry HOT 2 CLOSED

import 'package:built_value/serializer.dart';

/// A plugin that removes the `__typename` field from the serialized data.
class RemoveTypenamePlugin extends SerializerPlugin {
  @override
  Object? afterDeserialize(Object? object, FullType specifiedType) {
    return object;
  }

  @override
  Object? afterSerialize(Object? object, FullType specifiedType) {
    if (object is Map && object.containsKey('__typename')) {
      return Map<String, dynamic>.from(object as Map<String, dynamic>)..remove('__typename');
    } else {
      return object;
    }
  }

  @override
  Object? beforeDeserialize(Object? object, FullType specifiedType) {
    return object;
  }

  @override
  Object? beforeSerialize(Object? object, FullType specifiedType) {
    return object;
  }
}