@Throws(IOException::class)
    fun proceed(request: Request): Response

    /**
     * Returns the connection the request will be executed on. This is only available in the chains
     * of network interceptors; for application interceptors this is always null.
     */
    fun connection(): Connection?

    fun call(): Call

    fun connectTimeoutMillis(): Int

    fun withConnectTimeout(
      timeout: Int,

      val logHeaders = logBody || level == Level.HEADERS

      val requestBody = request.body

      val connection = chain.connection()
      var requestStartMessage =
        ("--> ${request.method} ${redactUrl(request.url)}${if (connection != null) " " + connection.protocol() else ""}")
      if (!logHeaders && requestBody != null) {
        requestStartMessage += " (${requestBody.contentLength()}-byte body)"

 * server.
 *
 * ## Preemptive Authentication
 *
 * To make HTTPS calls using an HTTP proxy server OkHttp must first negotiate a connection with
 * the proxy. This proxy connection is called a "TLS Tunnel" and is specified by
 * [RFC 2817][1]. The HTTP CONNECT request that creates this tunnel connection is special: it
 * does not participate in any [interceptors][Interceptor] or [event listeners][EventListener]. It

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")
    assertThat(recorded.headers["Accept-Encoding"]).isEqualTo("gzip, x-gzip, deflate")
    assertThat(recorded.headers["Connection"]).isEqualTo("keep-alive")
    assertThat(recorded.headers["User-Agent"]!!).startsWith("Apache-HttpClient/")
  }

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")
    assertThat(recorded.headers["Accept-Encoding"]).isNull() // No built-in gzip.
    assertThat(recorded.headers["Connection"]).isEqualTo("Upgrade, HTTP2-Settings")
    if (PlatformVersion.majorVersion < 19) {
      assertThat(recorded.headers["Content-Length"]).isEqualTo("0")
    }
    assertThat(recorded.headers["HTTP2-Settings"]).isNotNull()

  val connectTimeout: Int by option(
    "--connect-timeout",
    help = "Maximum time allowed for connection (seconds)",
  ).int().default(DEFAULT_TIMEOUT)

  val readTimeout: Int by option("--read-timeout", help = "Maximum time allowed for reading data (seconds)").int().default(DEFAULT_TIMEOUT)

  val callTimeout: Int by option(

address may also share the same underlying TCP socket connection. Sharing a connection has substantial performance benefits: lower latency, higher throughput (due to [TCP slow start](https://www.igvita.com/2011/10/20/faster-web-vs-tcp-slow-start/)) and conserved battery. OkHttp uses a [ConnectionPool](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-connection-pool/) that automatically reuses HTTP/1.x connections and multiplexes HTTP/2 connections.

In OkHttp some fields of the address come...

  @BeforeEach
  fun setUp(server: MockWebServer) {
    this.server = server
  }

  @Test
  fun clientSendsServerNameAndServerReceivesIt() {
    // java.net.ConnectException: Connection refused
    platform.assumeNotConscrypt()

    val handshakeCertificates = localhost()
    server.useHttps(handshakeCertificates.sslSocketFactory())

    val dns =
      Dns {

 * **ExchangeFinder** chooses which connection carries each exchange. Where possible it will use the same connection for all exchanges in a single call. It prefers reusing pooled connections over establishing new connections.      

#### Per-Connection Locks

    if (pooled3 != null) return pooled3.connection

    connection.withLock {
      connectionPool.put(connection)
      user.acquireConnectionNoEvents(connection)
    }

    user.connectionAcquired(connection)
    user.connectionConnectionAcquired(connection)
    return connection
  }

  override fun trackFailure(
    call: RealCall,
    e: IOException?,