* Added lock to Contains to avoid enumeration exceptions

OpenSim/Framework/BlockingQueue.cs

@@ -58,8 +58,11 @@ namespace OpenSim.Framework
         }
 
         public bool Contains(T item)
+        {
+            lock (m_queueSync)
             {
                 return m_queue.Contains(item);
             }
         }
+    }
 }