toJson method
Implementation
Map toJson(){
Map _result = {};
if (first != null) _result.addAll({"first": first!.toJson()});
if (second != null) _result.addAll({"second": second!.toJson()});
if (similarity != null) _result.addAll({"similarity": similarity});
if (score != null) _result.addAll({"score": score});
if (exception != null) _result.addAll({"exception": exception!.toJson()});
return _result;
}