I dont know how other developers, especially in consulting feel, but in several customer projects I have seen a difficulty when trying to access user logon information that is mapped onto a data source.
Internally, we store that as a hashtable with some "secret" keys and only provide enrich() methods for a URI or Java connector. If you want to implement custom enrich methods, you will have to disassemble the Java coding to find these secret keys.
Takes 30 mins and off you go.`
But wouldn't it be better to offer a standardized solution like a master authentification class to extend for these purposes?