}

  @Test
  @Throws(IOException::class)
  fun http1DoesntSupportDuplex() {
    val call =
      client.newCall(
        Request.Builder()
          .url(server.url("/"))
          .post(AsyncRequestBody())
          .build(),
      )
    assertFailsWith<ProtocolException> {
      call.execute()
    }
  }

  @Test
  fun trueDuplexClientWritesFirst() {
    enableProtocol(Protocol.HTTP_2)

    // Adapt the request and response into our Request and Response domain model.
    val scheme = if (request.handshake != null) "https" else "http"
    val authority = request.headers["Host"] // Has host and port.
    val fancyRequest =
      Request.Builder()
        .url("$scheme://$authority/")
        .headers(request.headers)
        .build()
    val fancyResponse =
      Response.Builder()

and increase connectivity with web servers.

### Certificate Pinning ([.kt][CertificatePinningKotlin], [.java][CertificatePinningJava])

        val host = url.host
        return host.substring(1, host.length - 5).lowercase()
      }

      override fun canonicalize(s: String): String = s.lowercase()
    },

    PATH {
      override fun urlString(value: String): String = "http://example.com/a${value}z/"

      override fun encodedValue(url: HttpUrl): String {
        val path = url.encodedPath
        return path.substring(2, path.length - 2)
      }

  fun encodeQuery(
    host: String,
    type: Int,
  ): ByteString =
    Buffer().apply {
      writeShort(0) // query id
      writeShort(256) // flags with recursion
      writeShort(1) // question count
      writeShort(0) // answerCount
      writeShort(0) // authorityResourceCount
      writeShort(0) // additional

      val nameBuf = Buffer()
      val labels = host.split('.').dropLastWhile { it.isEmpty() }

            challenge.scheme,
            url.toUrl(),
            Authenticator.RequestorType.PROXY,
          )
        } else {
          Authenticator.requestPasswordAuthentication(
            url.host,
            proxy.connectToInetAddress(url, dns),
            url.port,
            url.scheme,
            challenge.realm,
            challenge.scheme,
            url.toUrl(),

  public void run() throws Exception {
    final PipeBody pipeBody = new PipeBody();

    Request request = new Request.Builder()
        .url("https://api.github.com/markdown/raw")
        .post(pipeBody)
        .build();

    streamPrimesToSinkAsynchronously(pipeBody.sink());

    try (Response response = client.newCall(request).execute()) {

class AutobahnTester {
  val client = OkHttpClient()

  private fun newWebSocket(
    path: String,
    listener: WebSocketListener,
  ): WebSocket {
    val request =
      Request.Builder()
        .url(HOST + path)
        .build()
    return client.newWebSocket(request, listener)
  }

  fun run() {
    try {
      val count = getTestCount()
      println("Test count: $count")
      for (number in 1..count) {

  /**
   * Invoked just prior to a DNS lookup. See [Dns.lookup].
   *
   * This can be invoked more than 1 time for a single [Call]. For example, if the response to the
   * [Call.request] is a redirect to a different host.
   *
   * If the [Call] is able to reuse an existing pooled connection, this method will not be invoked.
   * See [ConnectionPool].
   */
  open fun dnsStart(
    call: Call,
    domainName: String,
  ) {

import java.net.UnknownHostException
import okhttp3.Dns

/**
 * Internal Bootstrap DNS implementation for handling initial connection to DNS over HTTPS server.
 *
 * Returns hardcoded results for the known host.
 */
internal class BootstrapDns(
  private val dnsHostname: String,
  private val dnsServers: List<InetAddress>,
) : Dns {
  @Throws(UnknownHostException::class)