once method
Listens for exactly one eventType
and then stops listening.
Implementation
Future<QueryEvent> once(String eventType) {
final c = Completer<QueryEvent>();
jsObject.once(eventType, allowInterop(
(database_interop.DataSnapshotJsImpl snapshot, [String? string]) {
c.complete(QueryEvent(DataSnapshot.getInstance(snapshot), string));
},
), resolveError(c));
return c.future;
}