private static void OnUpdated(object o, ExtensionNodeEventArgs args)
        {
            TypeExtensionNode node = (TypeExtensionNode)args.ExtensionNode;

            if (args.Change == ExtensionChange.Add)
            {
                provider = (BaseLocationProvider)node.CreateInstance();
                ThreadAssist.SpawnFromMain(() => {
                    RefreshGeoPosition();
                    NotifyObservers();
                });
            }
            else
            {
                provider = null;
            }
        }
        private static void OnUpdated(object o, ExtensionNodeEventArgs args)
        {
            TypeExtensionNode node = (TypeExtensionNode)args.ExtensionNode;

            if (args.Change == ExtensionChange.Add) {
                provider = (BaseLocationProvider)node.CreateInstance ();
                ThreadAssist.SpawnFromMain (() => {
                    RefreshGeoPosition ();
                    NotifyObservers ();
                });
            } else {
                provider = null;
            }
        }