Add region heartbeat start event to complement heartbeat end event.

This allows object modification before the usual heartbeat operation.

OpenSim/Region/Framework/Scenes/EventManager.cs

@@ -969,6 +969,8 @@ namespace OpenSim.Region.Framework.Scenes
         public delegate void RegionStarted(Scene scene);
         public event RegionStarted OnRegionStarted;
 
+        public delegate void RegionHeartbeatStart(Scene scene);
+        public event RegionHeartbeatStart OnRegionHeartbeatStart;
         public delegate void RegionHeartbeatEnd(Scene scene);
         public event RegionHeartbeatEnd OnRegionHeartbeatEnd;
 
@@ -3068,6 +3070,27 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
+        public void TriggerRegionHeartbeatStart(Scene scene)
+        {
+            RegionHeartbeatStart handler = OnRegionHeartbeatStart;
+
+            if (handler != null)
+            {
+                foreach (RegionHeartbeatStart d in handler.GetInvocationList())
+                {
+                    try
+                    {
+                        d(scene);
+                    }
+                    catch (Exception e)
+                    {
+                        m_log.ErrorFormat("[EVENT MANAGER]: Delegate for OnRegionHeartbeatStart failed - continuing {0} - {1}",
+                            e.Message, e.StackTrace);
+                    }
+                }
+            }
+        }
+
         public void TriggerRegionHeartbeatEnd(Scene scene)
         {
             RegionHeartbeatEnd handler = OnRegionHeartbeatEnd;

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -1517,6 +1517,8 @@ namespace OpenSim.Region.Framework.Scenes
 
                 try
                 {
+                    EventManager.TriggerRegionHeartbeatStart(this);
+
                     // Apply taints in terrain module to terrain in physics scene
                     if (Frame % m_update_terrain == 0)
                     {