ProtectedcheckingProtectedcheckProtectedinsertedProtectedlastProtectedloadedItems waiting behind the "new" pill.
ReadonlysourceSomething may have changed while the column was off screen.
ReadonlytypeHands a realtime event to the source. Most are handled from the payload alone; those only the server can place queue a check of this column.
Whether realtime is connected. Live columns take new items straight away; otherwise they wait behind the "new" pill.
See DeckColumnSource.prune().
However many events arrive, a column asks the server at most every MIN_CHECK_INTERVAL.
Items were just inserted above the reader; the component keeps their place.