code: def test_boundless_msk_vrt(path_rgb_msk_byte_tif):
      with rasterio.open(path_rgb_msk_byte_tif) as msk:
          doc = rasterio.vrt._boundless_vrt_doc(msk)
          assert doc.startswith("<VRTDataset")
          with rasterio.open(doc) as vrt:
              assert msk.count == vrt.count
              assert msk.dtypes == vrt.dtypes
              assert msk.mask_flag_enums == vrt.mask_flag_enums
  
label_desc: Use image node_id 2 for calling a global function with example usage: test_boundless_msk_vrt(path_rgb_msk_byte_tif) without return types