}

	// 5. Drop
	dropNotLatin := func(r rune) rune {
		if unicode.Is(unicode.Latin, r) {
			return r
		}
		return -1
	}
	m = Map(dropNotLatin, []byte("Hello, 세계"))
	expect = "Hello"
	if string(m) != expect {
		t.Errorf("drop: expected %q got %q", expect, m)
	}

	// 6. Invalid rune
	invalidRune := func(r rune) rune {
		return utf8.MaxRune + 1
	}

		Long: `Analyzes pod, its Services, DestinationRules, and VirtualServices and reports
the configuration objects that affect that pod.`,
		Example: `  istioctl experimental describe pod productpage-v1-c7765c886-7zzd4`,
		RunE: func(cmd *cobra.Command, args []string) error {
			describeNamespace = ctx.NamespaceOrDefault(ctx.Namespace())
			if len(args) != 1 {
				return fmt.Errorf("expecting pod name")
			}

	f.NoCallbacks = make(map[string]bool)
	f.NoEscapes = make(map[string]bool)
	for _, line := range linesIn {
		l := strings.TrimSpace(line)
		if len(l) < 5 || l[:4] != "#cgo" || !unicode.IsSpace(rune(l[4])) {
			linesOut = append(linesOut, line)
		} else {
			linesOut = append(linesOut, "")

			// #cgo (nocallback|noescape) <function name>
			if fields := strings.Fields(l); len(fields) == 3 {

	} else if err != io.EOF {
		t.Error("expected EOF; got", err)
	}
}

func TestReadWriteRune(t *testing.T) {
	const NRune = 1000
	byteBuf := new(bytes.Buffer)
	w := NewWriter(byteBuf)
	// Write the runes out using WriteRune
	buf := make([]byte, utf8.UTFMax)
	for r := rune(0); r < NRune; r++ {
		size := utf8.EncodeRune(buf, r)
		nbytes, err := w.WriteRune(r)
		if err != nil {