",  }   err = emit(cc.HandleChange, changeStream(ch))  require.NoError(t, err)   _, err = cc.Checksum(context.TODO(), ref, "d0", true)  require.Error(t, err)  require.Equal(t, true, errors.Is(err, errNotFound))   _, err = cc.Checksum(context.TODO(), ref, "d0/abc", true)  require.Error(t, err)  require.Equal(t, true, errors.Is(err, errNotFound))   err = ref.Release(context.TODO())  require.NoError(t, err) }  func TestHandle