anchor.diff:  class _MapSerializer extends _BaseSerializer {
     _MapSerializer(model, serializer) : super(model, serializer);
   
  -  readFromSerializer(field) => serializer.custom[field](model);
  +  serialize(){
  +    var res = fields.fold({}, (Map res, String field) {
  +      if (serializerOverrides(field)) {
  +        res[field] = readFromSerializer(field);
  +      } else {
  +        res[field] = readFromModel(field);
  +      }
  +      return res;
  +    });
  +    return postProcessing(res);
  +  }
   
  -  readFromModel(field) => model[field];
  +  readFromSerializer(String field) => serializer.custom[field](model);
  +
  +  readFromModel(String field) => model[field];
   }
  
positive.code:     return serializer.postProcessing(withRoot, model);
    }
  
    serialize(){
      var res = fields.reduce({}, (Map res, String field) {
        if(serializerOverrides(field)){
          res[field] = readFromSerializer(field);
        } else {
          res[field] = readFromModel(field);
  
negative.code:     if(object == true){
        return new _AsyncSerializer(m, this).serialize();
      } else {
        return new Future.sync(() => new _MapSerializer(m, this).serialize());
      }
    }
  }
  