ConstReadonlyPending: "pending"The cell's own function asked for its result later (FormulaContext.defer) and it has not
arrived: the cell shows what the function returned meanwhile, and its dependents calculate
from that and read as Waiting. A failed call answers an error value.
ReadonlyReady: "ready"The value is up-to-date and reflects the latest calculation.
ReadonlyStale: "stale"The value may not reflect the latest calculation, typically due to the calculation engine being in manual mode.
ReadonlyWaiting: "waiting"The value was calculated from a pending value — a precedent whose function has not answered — and will be calculated again when it does.
Represents the status of a calculation result