llClientView: try to have only one thread per client processing

RegionHandleRequests. (code assumes packet handle is called async as it is not)

OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs

@@ -8751,16 +8751,61 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
         #region Parcel related packets
 
+        // acumulate several HandleRegionHandleRequest consecutive overlaping requests
+        // to be done with minimal resources as possible
+        // variables temporary here while in test
+
+        Queue<UUID> RegionHandleRequests = new Queue<UUID>();
+        bool RegionHandleRequestsInService = false;
+
         private bool HandleRegionHandleRequest(IClientAPI sender, Packet Pack)
         {
-            RegionHandleRequestPacket rhrPack = (RegionHandleRequestPacket)Pack;
+            UUID currentUUID;
 
             RegionHandleRequest handlerRegionHandleRequest = OnRegionHandleRequest;
-            if (handlerRegionHandleRequest != null)
+
-            {
+            if (handlerRegionHandleRequest == null)
-                handlerRegionHandleRequest(this, rhrPack.RequestBlock.RegionID);
-            }
                 return true;
+
+            RegionHandleRequestPacket rhrPack = (RegionHandleRequestPacket)Pack;
+
+            lock (RegionHandleRequests)
+            {
+                if (RegionHandleRequestsInService)
+                {
+                    // we are already busy doing a previus request
+                    // so enqueue it
+                    RegionHandleRequests.Enqueue(rhrPack.RequestBlock.RegionID);
+                    return true;
+                }
+
+                // else do it
+                currentUUID = rhrPack.RequestBlock.RegionID;
+                RegionHandleRequestsInService = true;
+            }
+
+            while (true)
+            {
+                handlerRegionHandleRequest(this, currentUUID);
+
+                lock (RegionHandleRequests)
+                {
+                    // exit condition, nothing to do or closed
+                    // current code seems to assume we may loose the handler at anytime,
+                    // so keep checking it
+                    handlerRegionHandleRequest = OnRegionHandleRequest;
+
+                    if (RegionHandleRequests.Count == 0 || !IsActive || handlerRegionHandleRequest == null)
+                    {
+                        RegionHandleRequests.Clear();
+                        RegionHandleRequestsInService = false;
+                        return true;
+                    }
+                    currentUUID = RegionHandleRequests.Dequeue();
+                }
+            }
+
+            return true; // actually unreached
         }
 
         private bool HandleParcelInfoRequest(IClientAPI sender, Packet Pack)