Scan(t *testing.T) {  t.Parallel()  tmpdir, err := ioutil.TempDir("", "buildkit-state")  require.NoError(t, err)  defer os.RemoveAll(tmpdir)   snapshotter, err := native.NewSnapshotter(filepath.Join(tmpdir, "snapshots"))  require.NoError(t, err)  cm, _ := setupCacheManager(t, tmpdir, "native", snapshotter)  defer cm.Close()   ch := []string{   "ADD a