public HistoryTracker(IEnumerable <string> storedHistory, HistoryStorageHandler storageHandler)
 {
     history = storedHistory.ToHashSet();
     this._storageHandler = storageHandler;
 }
 public HistoryTracker(HistoryStorageHandler storageHandler)
 {
     this._storageHandler = storageHandler;
     history = _storageHandler.GetAllHistory().ToHashSet();
 }