StartTFNLookup: tries to locate a duplicated remote profile by URI; federation plugins must trigger this event before profile insertion
@param string $uri URI of the remote profile to be inserted
@param string $class profile class of the federation protocol that triggered the event
@param int|null &$profile_id profile ID associated with the duplicated remote profile found, throws AlreadyHandledException to warn that the duplicate has priority

EndTFNLookup: deletes a previous duplicated remote profile found; federation plugins must trigget this event after successfully inserting a new profile
@param string $class profile class of the federation protocol that triggered the event
@param int &$profile_id profile ID associated with the duplicated remote profile