 file data0",  }   ref := createRef(t, cm, nil)   cc, err := newCacheContext(ref.Metadata(), nil)  require.NoError(t, err)   err = emit(cc.HandleChange, changeStream(ch))  require.NoError(t, err)   dgst, err := cc.Checksum(context.TODO(), ref, "d0", true)  require.NoError(t, err)   require.Equal(t, dgst