anchor.diff:    // See chat_example and end_to_end_test for more complex usage!
   }
   
  -/// Example of using StandardJsonPlugin.
  +/// Examples of using StandardJsonPlugin.
   ///
   /// The plugin changes the built_value serialization format to the Map-based
   /// format used by most JSON APIs.
  
positive.code: /// a `discriminator` field. By default this field is called `$`; you can pass
  /// a different name to the `StandardJsonPlugin` constructor. If the wire
  /// format should not contain the type name, you must instead explicitly
  /// specify which type to serialize/deserialize.
  void standardJsonExample() {
    final standardSerializers =
        (serializers.toBuilder()..addPlugin(new StandardJsonPlugin())).build();
  
    final serializedAccount = {
      'id': 3,
      'name': 'John Smith',
  
negative.code:   final serializedAgain =
        standardSerializers.serializeWith(Account.serializer, value);
    assert(serializedAccount.toString() == serializedAgain.toString());
  
    // In this second example we don't know the type we want to
    // serialize/deserialize, so it has to be specified on the wire.
    final serializedAccountWithDiscriminator = {
      r'$': 'Account',
      'id': 3,
      'name': 'John Smith',
      'keyValues': {
        'visited': 1732,
        'active': true,
        'email': 'john.smith@example.com',
        'tags': [74, 123, 4001],
        'preferences': {
          'showMenu': true,
          'skipIntro': true,
          'colorScheme': 'light',
        }
      }
    };
  
    // We don't have to specify the type when deserializing.
    final value2 =
        standardSerializers.deserialize(serializedAccountWithDiscriminator);
    print(value2);
    assert(value == value2);
  
    // We don't have to specify the type when serializing.
    final serializedAgain2 = serializers.serialize(value2);
    assert(serializedAccountWithDiscriminator.toString ==
        serializedAgain2.toString());
  }
  