Custom attributes support
GitLab supports custom attributes on certain resources (Users, Groups, Projects, etc.) and this library (and the GL API) seems to support searching based on these, but there is no easy way to access and manipulate them.
Accessing these is probably a priority over attribute manipulation at the moment.
Since there is no attributes field returned as a part of the resource query API (the GraphQL API does not support this either!) and has to be requested using a separate API, this issue is mainly to discuss the best possible implementation before we go and do anything.
Any thoughts?