close method
Closes the server and returns a future that completes when all resources are released.
Implementation
@override
Future<void> close({bool force = false}) async {
Future<void> close(IsolateSupervisor supervisor) async {
await supervisor.stop(force: force);
}
await Future.wait<void>(supervisors.map<Future<void>>(close));
supervisors.clear();
isRunning = false;
}