Some directory-watcher rework - still not working properly

MediaBrowser.Controller/Entities/BaseItem.cs

@@ -2,6 +2,7 @@
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.IO;
 using System;
+using System.Threading.Tasks;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -179,5 +180,14 @@ namespace MediaBrowser.Controller.Entities
                 data.PlaybackPositionTicks = 0;
             }
         }
+
+        /// <summary>
+        /// Do whatever refreshing is necessary when the filesystem pertaining to this item has changed.
+        /// </summary>
+        /// <returns></returns>
+        public virtual Task ChangedExternally()
+        {
+            return Task.Run(() => RefreshMetadata());
+        }
     }
 }