Dismiss the busy indicator.
Update the message shown beside the indicator.
Update the indicator to a determinate state. When total is known the indicator shows a
percentage / progress bar; passing total as undefined (or completed as undefined)
returns it to the indeterminate (spinner) state.
Optionalcompleted: number
The cumulative work done so far.
Optionaltotal: number
The total work, in the same units as completed.
The handle returned by IReactNotifier.showBusy.
Remarks
It is callable — calling it dismisses the busy indicator (the historical
hideBusy()contract) — and also carries methods to update the indicator while it is showing. This keeps every existingconst hideBusy = await showBusy(...); hideBusy();call working unchanged.