This is a Moo extension. It allows other attributes for Moo/has. If any of these are given, then Moo/BUILDARGS is wrapped so that values for object attributes can, if not supplied in the normal construction process, come from the environment.
The environment will be searched for either the given case, or upper case, version of the names discussed below.
When a prefix is mentioned, it will be prepended to the mentioned name, with a '_' in between.