readMapData method
Reads complete map data for a rectangular area.
Combines map data from all tiles within the specified area. Default implementations may be inefficient for large areas.
Precondition: upperLeft.tileX <= lowerRight.tileX && upperLeft.tileY <= lowerRight.tileY
upperLeft Upper-left corner tile of the requested area
lowerRight Lower-right corner tile of the requested area
Returns combined map data for the entire area
Implementation
@override
Future<DatastoreBundle> readMapData(Tile upperLeft, Tile lowerRight) {
// TODO: implement readMapData
throw UnimplementedError();
}