char c;
        for (int i = 0; i < in.length(); i++) {
            c = in.charAt(i);
            if (c == 0x9 || c == 0xA || c == 0xD || c >= 0x20 && c <= 0xD7FF || c >= 0xE000 && c <= 0xFFFD
                    || c >= 0x10000 && c <= 0x10FFFF) {
                buf.append(c);
            }
        }
        return buf.toString().trim();
    }

	repl string
	out  string
}{
	{"", "\uFFFD", ""},
	{"abc", "\uFFFD", "abc"},
	{"\uFDDD", "\uFFFD", "\uFDDD"},
	{"a\xffb", "\uFFFD", "a\uFFFDb"},
	{"a\xffb\uFFFD", "X", "aXb\uFFFD"},
	{"a☺\xffb☺\xC0\xAFc☺\xff", "", "a☺b☺c☺"},
	{"a☺\xffb☺\xC0\xAFc☺\xff", "日本語", "a☺日本語b☺日本語c☺日本語"},
	{"\xC0\xAF", "\uFFFD", "\uFFFD"},
	{"\xE0\x80\xAF", "\uFFFD", "\uFFFD"},
	{"\xed\xa0\x80", "abc", "abc"},

      0x76, 0x2c, 0x8, 0x9, 0x2d, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7ffe, 0x7fc, 0x3ffd, 0x1ffd,
      0xffffffc, 0xfffe6, 0x3fffd2, 0xfffe7, 0xfffe8, 0x3fffd3, 0x3fffd4, 0x3fffd5, 0x7fffd9,
      0x3fffd6, 0x7fffda, 0x7fffdb, 0x7fffdc, 0x7fffdd, 0x7fffde, 0xffffeb, 0x7fffdf,
      0xffffec, 0xffffed, 0x3fffd7, 0x7fffe0, 0xffffee, 0x7fffe1, 0x7fffe2, 0x7fffe3,
      0x7fffe4, 0x1fffdc, 0x3fffd8, 0x7fffe5, 0x3fffd9, 0x7fffe6, 0x7fffe7, 0xffffef,

-A PREROUTING -j ISTIO_PRERT
-A OUTPUT -j ISTIO_OUTPUT
-A ISTIO_PRERT -m mark --mark 0x539/0xfff -j CONNMARK --set-xmark 0x111/0xfff
-A ISTIO_PRERT -s 169.254.7.127 -p tcp -m tcp -j ACCEPT
-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp -i lo -j ACCEPT
-A ISTIO_PRERT -p tcp -m tcp --dport 15008 -m mark ! --mark 0x539/0xfff -j TPROXY --on-port 15008 --tproxy-mark 0x111/0xfff
-A ISTIO_PRERT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp ! --dport 15008 -m mark ! --mark 0x539/0xfff -j REDIRECT --to-ports 15006
-A ISTIO_OUTPUT ! -o lo -p udp -m mark ! --mark 0x539/0xfff -m udp --dport 53 -j REDIRECT --to-port 15053
-A ISTIO_OUTPUT ! -d 127.0.0.1/32 -p tcp --dport 53 -m mark ! --mark 0x539/0xfff -j REDIRECT --to-ports 15053
-A ISTIO_OUTPUT -p tcp -m mark --mark 0x111/0xfff -j ACCEPT
-A ISTIO_OUTPUT ! -d 127.0.0.1/32 -o lo -j ACCEPT

    val flags = buf.readShort().toInt() and 0xffff
    require(flags shr 15 != 0) { "not a response" }

    val responseCode = flags and 0xf

    if (responseCode == NXDOMAIN) {
      throw UnknownHostException("$hostname: NXDOMAIN")
    } else if (responseCode == SERVFAIL) {
      throw UnknownHostException("$hostname: SERVFAIL")
    }

    val questionCount = buf.readShort().toInt() and 0xffff

-A OUTPUT -j ISTIO_OUTPUT
-A ISTIO_OUTPUT -m connmark --mark 0x111/0xfff -j CONNMARK --restore-mark --nfmask 0xffffffff --ctmask 0xffffffff
COMMIT
* nat
-N ISTIO_OUTPUT
-N ISTIO_PRERT
-A OUTPUT -j ISTIO_OUTPUT
-A PREROUTING -j ISTIO_PRERT
-A ISTIO_OUTPUT -d 169.254.7.127 -p tcp -m tcp -j ACCEPT
-A ISTIO_OUTPUT -p tcp -m mark --mark 0x111/0xfff -j ACCEPT
-A ISTIO_OUTPUT ! -d 127.0.0.1/32 -o lo -j ACCEPT

    assertEquals("The Quick Brown Fox", escaper.escape("The Quick Brown Fox"));
  }

  public void testBuilderInitialStateNoneUnsafe() {
    // No characters are unsafe by default (safeMin == 0, safeMax == 0xFFFF).
    Escaper escaper = Escapers.builder().setUnsafeReplacement("X").build();
    assertEquals("\0\uFFFF", escaper.escape("\0\uFFFF"));
  }

  public void testBuilderRetainsState() {

      checkArgument(
          (port >= 0) && (port <= 0xffff), "port '%s' is out of range (0 <= port <= 0xffff)", port);
      checkArgument(
          (flags >= 0) && (flags <= 0xffff),
          "flags '%s' is out of range (0 <= flags <= 0xffff)",
          flags);

      this.server = MoreObjects.firstNonNull(server, ANY4);

string containing the UTF-8 representation of the integer. Values outside
the range of valid Unicode code points are converted to <code>"\uFFFD"</code>.

<pre>
string('a')       // "a"
string(-1)        // "\ufffd" == "\xef\xbf\xbd"
string(0xf8)      // "\u00f8" == "ø" == "\xc3\xb8"
type MyString string
MyString(0x65e5)  // "\u65e5" == "日" == "\xe6\x97\xa5"
</pre>
</li>