def METHOD_NAME(rgb_byte_tif_reader):
    with rgb_byte_tif_reader as src:
        data = src.read(
            window=((-200, 200), (-200, 200)), boundless=True, masked=True)
        assert data.shape == (3, 400, 400)
        assert data.mask.any()
        assert not data.mask.all()
        assert not data.mask[0, 399, 399]
        assert data.mask[0, 0, 0]