public FolderSubscription(FolderWatcherExtension instance, string folder, string pattern, bool subfolders)
     : this(instance)
 {
     this.watcher = new System.IO.FileSystemWatcher(folder, pattern ?? "*.*")
     {
         IncludeSubdirectories = subfolders
     };
 }
 public FolderSubscription(FolderWatcherExtension instance)
 {
     this.instance = instance;
 }