public void Add(Vector2Int32 location, Tile tile) { var undoTile = new UndoTile(location, tile); if (undoTile == null) { throw new Exception("Null undo?"); } lock (UndoSaveLock) { UndoTiles.Add(undoTile); LastTile = undoTile; } if (UndoTiles.Count > FlushSize) { Flush(); } }