The observer that will be hooked into the observable in the associated canonical Auto\-Segment. Used to propagate the invalidation/revalidation events from Auto\-Segment toward \hyperlink{classKite_1_1TrackSegment}{Track\-Segment}.
As a secondary function, it is used by the \hyperlink{classKite_1_1Session_a1728621b96081c32fb7bfb18a0ebfad3}{Session\-::lookup()} method to quicly retrieve \hyperlink{classKite_1_1TrackSegment}{Track\-Segment} from {\bf Katabatic\-::\-Auto\-Segment}.
Implement the asymmetric invalidate/revalidate policy described in \hyperlink{classKite_1_1Session}{Kite\-::\-Session}. The invalidate is immediatly passed on while the revalidate is ignored.