Opc.Ua.Server.Subscription.ConstructMessage C# (CSharp) Method

        private NotificationMessage ConstructMessage(
            Queue<EventFieldList> events,
            Queue<MonitoredItemNotification> datachanges,
            Queue<DiagnosticInfo> datachangeDiagnostics,
            out int notificationCount)
        {
            notificationCount = 0;

            NotificationMessage message = new NotificationMessage();

            message.SequenceNumber = (uint)m_sequenceNumber; 
            message.PublishTime    = DateTime.UtcNow;

            Utils.IncrementIdentifier(ref m_sequenceNumber);

            lock (m_diagnostics)
            {
                m_diagnostics.NextSequenceNumber = (uint)m_sequenceNumber;
            }
             
            // add events.
            if (events.Count > 0 && notificationCount < m_maxNotificationsPerPublish)
            {
                EventNotificationList notification = new EventNotificationList();

                while (events.Count > 0 && notificationCount < m_maxNotificationsPerPublish)
                {
                    notification.Events.Add(events.Dequeue());
                    notificationCount++;
                }

                message.NotificationData.Add(new ExtensionObject(notification));
            }

            // add datachanges (space permitting).
            if (datachanges.Count > 0 && notificationCount < m_maxNotificationsPerPublish)
            {
                bool diagnosticsExist = false;
                DataChangeNotification notification = new DataChangeNotification();

                notification.MonitoredItems  = new MonitoredItemNotificationCollection(datachanges.Count);
                notification.DiagnosticInfos = new DiagnosticInfoCollection(datachanges.Count);

                while (datachanges.Count > 0 && notificationCount < m_maxNotificationsPerPublish)
                {
                    MonitoredItemNotification datachange = datachanges.Dequeue();
                    notification.MonitoredItems.Add(datachange);

                    DiagnosticInfo diagnosticInfo = datachangeDiagnostics.Dequeue();

                    if (diagnosticInfo != null)
                    {
                        diagnosticsExist = true;
                    }
                    
                    notification.DiagnosticInfos.Add(diagnosticInfo);

                    notificationCount++;
                }

                // clear diagnostics if not used.
                if (!diagnosticsExist)
                {
                    notification.DiagnosticInfos.Clear();
                }

                message.NotificationData.Add(new ExtensionObject(notification));
            }

            return message;
        }