A ReprovisionRequested in flight from an old incarnation could reach the NEW child
after HandleRestartDriver swapped it in. In Connecting that child DOES handle
InitializeRequested, so it started a second concurrent InitializeAsync, racing the
#527 dispose-before-overwrite.
Seen RED: InitializeCount == 2 on a child held in Connecting by a gated init
(an already-connected child swallows InitializeRequested and passes vacuously).
Joseph Doherty
2b7100cf19