slurp doesn't properly handle URLs that contain authentication information

Because of limitations in the underlying Java classes [[1]|https://stackoverflow.com/questions/496651/connecting-to-remote-url-which-requires-authentication-using-java], clojure.core/slurp doesn't support URLs that contain authentication information i.e. https://user:password@hostname.domain/path/to/resource. It would be great if slurp did support this (e.g. by using Java's UrlConnection class, as suggested in [1]), so that application code doesn't have to include special cases for different types of input string that will be sent to slurp.

[1] https://stackoverflow.com/questions/496651/connecting-to-remote-url-which-requires-authentication-using-java

Approach: Check to see if url contains userInfo, if so, open a connection, set authorisation on it and return its input stream. Otherwise call `openStream` on the url as before
Limitations: This approach uses java.xml.bind.DatatypeConverter, which is known to not work with java9