.bootstrapDnsHosts(InetAddress.getByName("8.8.4.4"), InetAddress.getByName("8.8.8.8"))
    .build()

  val client = bootstrapClient.newBuilder().dns(dns).build()
```

}

/**
 * Returns the canonical address for [address]. If [address] is an IPv6 address that is mapped to an
 * IPv4 address, this returns the IPv4-mapped address. Otherwise, this returns [address].
 *
 * https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses
 */
internal fun canonicalizeInetAddress(address: ByteArray): ByteArray {
  return when {
    isMappedIpv4Address(address) -> address.sliceArray(12 until 16)

    // mongolian vowel separator
    assertThat(parse("http://h/\u180e").encodedPath).isEqualTo("/%E1%A0%8E")
    // en quad
    assertThat(parse("http://h/\u2000").encodedPath).isEqualTo("/%E2%80%80")
    // em quad
    assertThat(parse("http://h/\u2001").encodedPath).isEqualTo("/%E2%80%81")
    // en space
    assertThat(parse("http://h/\u2002").encodedPath).isEqualTo("/%E2%80%82")
    // em space

cc

// cd : https://en.wikipedia.org/wiki/.cd
// see also: https://www.nic.cd/domain/insertDomain_2.jsp?act=1
cd
gov.cd

// cf : https://en.wikipedia.org/wiki/.cf
cf

// cg : https://en.wikipedia.org/wiki/.cg
cg

// ch : https://en.wikipedia.org/wiki/.ch
ch

// ci : https://en.wikipedia.org/wiki/.ci
// http://www.nic.ci/index.php?page=charte
ci
org.ci
or.ci
com.ci

        .addHeader("Accept-Language", "en-US")
        .build()
    val response1 = client.newCall(request1).execute()
    assertThat(response1.body.string()).isEqualTo("A")
    val request2 =
      Request.Builder()
        .url(url)
        .addHeader("Accept-Language", "fr-CA, fr-FR")
        .addHeader("Accept-Language", "en-US")
        .build()

release. For example, in OkHttp 2.2 we dropped support for SSL 3.0 in response to the [POODLE](https://googleonlinesecurity.blogspot.ca/2014/10/this-poodle-bites-exploiting-ssl-30.html) attack. And in OkHttp 2.3 we dropped support for [RC4](https://en.wikipedia.org/wiki/RC4#Security). As with your desktop web browser, staying up-to-date with OkHttp is the best way to stay secure.

You can build your own connection spec with a custom set of TLS versions and cipher suites. For example, this...

    // System.setProperty("jdk.tls.server.enableSessionTicketExtension", "true")

    platform.assumeJdk9()
  }

  @Test
  fun testTlsv13Works() {
    // https://docs.oracle.com/en/java/javase/14/security/java-secure-socket-extension-jsse-reference-guide.html
    // TODO test jdk.tls.client.enableSessionTicketExtension
    // TODO check debugging information

    enableTls()

  private val client = OkHttpClient()

  fun run() {
    val formBody =
      FormBody.Builder()
        .add("search", "Jurassic Park")
        .build()
    val request =
      Request(
        url = "https://en.wikipedia.org/w/index.php".toHttpUrl(),
        body = formBody,
      )

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

  public void run() throws Exception {
    RequestBody formBody = new FormBody.Builder()
        .add("search", "Jurassic Park")
        .build();
    Request request = new Request.Builder()
        .url("https://en.wikipedia.org/w/index.php")
        .post(formBody)
        .build();

    try (Response response = client.newCall(request).execute()) {
      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

   00A0; NO-BREAK SPACE
   1680; OGHAM SPACE MARK
   2000; EN QUAD
   2001; EM QUAD
   2002; EN SPACE
   2003; EM SPACE
   2004; THREE-PER-EM SPACE
   2005; FOUR-PER-EM SPACE
   2006; SIX-PER-EM SPACE
   2007; FIGURE SPACE
   2008; PUNCTUATION SPACE
   2009; THIN SPACE
   200A; HAIR SPACE
   200B; ZERO WIDTH SPACE
   202F; NARROW NO-BREAK SPACE
   205F; MEDIUM MATHEMATICAL SPACE