code: def _get_spatial_bounds(self):
           
          # This should be a MultiRasterIO method
          with rasterio.open(self._mrio._get_template_for_given_resolution(self._mrio.dst_res, "path")) as src_layer:
              pass # later we need src_layer for src_layer.window_transform(win)
          win_transform = src_layer.window_transform(self._window)
          bounds = rasterio.windows.bounds(window=self._window,
                                           transform=win_transform,
                                           height=0, width=0)
          return bounds
docs: Get the spatial bounds of the chunk.