onSettled property
Runs after onSuccess or onError and the cache-wide
MutationCache.onSettled, with whichever of data and error
applies. A returned future is awaited, and the mutation stays pending
until it completes — return an invalidation's future to report success
only once the refetch is done. No default.
Implementation
final OnMutationSettled<TData, TVariables, TOnMutateResult>? onSettled;