I'm certainly saying the same as @battags.

Previously, the authentication was performed on ```transformedUsername``` and ```credential.getPassword``` and the metadata were built on the original ```credential```.

With your proposed change, the authentication is also performed on ```transformedUsername``` and ```credential.getPassword```, but if you use ```createHandlerResult```, you will build the metadata on the provided ```credential```, which has been transformed and is therefore no more the original one.