Stop LLUDPServer sending updates after object deletes by always queueing deletes

If an LL 1.23.5 client (and possibly earlier and later) receives an object update after a kill object packet, it leaves the deleted prim in the scene until client relog
This is possible in LLUDPServer if an object update packet is queued but a kill packet sent immediately.
Beyond invasive tracking of kill sending, most expedient solution is to always queue kills, so that they always arrive after updates.
In tests, this doesn't appear to affect performance.
There is probably still an issue present where an update packet might not be acked and then resent after the kill packet.

1 files changed, 6 insertions, 2 deletions

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
index ff4abf8..e54cfc2 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
@@ -410,7 +410,11 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             OutgoingPacket outgoingPacket = new OutgoingPacket(udpClient, buffer, category);
 
-            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket))
+            // If a Linden Lab 1.23.5 client receives an update packet after a kill packet for an object, it will 
+            // continue to display the deleted object until relog.  Therefore, we need to always queue a kill object
+            // packet so that it isn't sent before a queued update packet.
+            bool requestQueue = type == PacketType.KillObject;
+            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, requestQueue))
                 SendPacketFinal(outgoingPacket);
 
             #endregion Queue or Send
@@ -503,7 +507,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     //Interlocked.Increment(ref Stats.ResentPackets);
 
                     // Requeue or resend the packet
-                    if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket))
+                    if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket, false))
                         SendPacketFinal(outgoingPacket);
                 }
             }