error BadService()
error ServiceNotAvailable()
error ConflictingRecordFound()
+error EnumerationNotSupported()
```
The `GetUserRecord` method looks up or enumerates a user record. If the `uid`
and another service that defines a group B, and a third service that declares
that A is a member of B.
+Looking up explicit users/groups by their name or UID/GID, or querying
+user/group memberships must be supported by all services implementing these
+interfaces. However, supporting enumeration (i.e. user/group lookups that may
+result in more than one reply, because neither UID/GID nor name is specified)
+is optional. Services which are asked for enumeration may return the
+`EnumerationNotSupported` error in this case.
+
And that's really all there is to it.