[Server] Improve publishing operation to avoid discarding values in edge cases

Libraries/Opc.Ua.Server/Subscription/MonitoredItem.cs

@@ -1190,7 +1190,7 @@
                     }
 
 
                     int notificationCount = overflowEvent != null ? 1 : 0;
 
                     for (int ii = 0; ii < m_events.Count; ii++)
                     {
@@ -1218,7 +1218,7 @@
 
                         notifications.Enqueue(m_events[ii]);
 
-                        m_events.RemoveAt(ii);
+                        m_events.RemoveAt(ii--);
                     }
 
                     // place event at the end of the queue.
@@ -1234,11 +1234,11 @@
 
                 // reset state variables.
                 m_overflow = m_overflow && moreValuesToPublish && !m_discardOldest;
                 m_readyToPublish = moreValuesToPublish;
                 m_readyToTrigger = moreValuesToPublish;
                 m_triggered = false;
 
                 return moreValuesToPublish;
             }
         }
 

Libraries/Opc.Ua.Server/Subscription/Subscription.cs

@@ -862,10 +862,13 @@
                     }
                     else
                     {
                         hasMoreValuesToPublish = ((IEventMonitoredItem)monitoredItem).Publish(context, events, maxNotificationsPerMonitoredItem);
                     }
 
-                    // add back to list to check.
+                    // if item has more values to publish leave it at the front of the list
+                    // to execute publish in next cycle, no checking needed
+                    // if no more values to publish are left add it to m_itemsToCheck
+                    // to check status on next publish cylce
                     if (!hasMoreValuesToPublish)
                     {
                         m_itemsToPublish.Remove(current);