public long EnqueuedCount(string queue)
        {
            if (string.IsNullOrEmpty(queue))
            {
                throw new ArgumentNullException(nameof(queue));
            }

            IPersistentJobQueueProvider      provider      = storage.QueueProviders.GetProvider(queue);
            IPersistentJobQueueMonitoringApi monitoringApi = provider.GetJobQueueMonitoringApi();

            return(monitoringApi.GetEnqueuedCount(queue));
        }