commitAsync method
Commits the changes to the Realm asynchronously.
Canceling the commit using the cancellationToken will not abort the transaction, but
rather resolve the future immediately with a CancelledException.
Implementation
Future<void> commitAsync([CancellationToken? cancellationToken]) async {
  final realm = _ensureOpen('commitAsync');
  await realm.handle.commitWriteAsync(cancellationToken);
  _closeTransaction();
}