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Clouds: Purge deleted folder
As long as the folder is in Trash, you can purge it completely it by calling TElBoxFolder.Purge() method. After calling this method the instance of TElBoxFolder is destroyed and you should not use it further.
C#:
TElBoxFolder trashedFolder = storage.AcquireTrashedFolder(@"...");
Console.WriteLine("Folder: {0}", trashedFolder.Name);
trashedFolder.Purge();