public Task <MqttClientSubscribeResult[]> ReSubscribeAllAsync(CancellationToken cancellationToken = default) { var subscribers = _subsManager.AllTopics().Select(async topic => { if (await _mqttPersisterConnection.TryConnectAsync(cancellationToken: cancellationToken)) { return(await OnSubscribesAsync(topic)); } return(null); }); return(Task.WhenAll(subscribers)); }