Whether the fiber sits in a subtree React is hiding but preserving
(Suspense fallback shown, Activity hidden). Distinguishes an effect
teardown caused by hiding from a real unmount.
May false-positive via a stale alternate that still records an old
hide; callers must tolerate that (e.g. by checking isFiberLive once
the commit ends).
Whether the fiber sits in a subtree React is hiding but preserving (Suspense fallback shown, Activity hidden). Distinguishes an effect teardown caused by hiding from a real unmount.
May false-positive via a stale alternate that still records an old hide; callers must tolerate that (e.g. by checking isFiberLive once the commit ends).