private void AddFoldersRecusive(Folders folders, Dictionary<string, List<Tuple<string, string>>> collector)
{
// TODO: do not add "Deleted Items"-Folder
foreach (var folder in folders.Cast<Folder> ().ToSafeEnumerable ())
{
AddFoldersRecusive(folder.Folders, collector);
collector.GetOrAdd(folder.Name).Add(Tuple.Create(folder.EntryID, folder.StoreID));
}
}