trackFailure(e)
      throw e
    }
  }

  @Throws(IOException::class)
  fun peekTrailers(): Headers? = codec.peekTrailers()

  fun upgradeToSocket(): Socket {
    call.upgradeToSocket()
    (codec.carrier as RealConnection).useAsSocket()

    return object : Socket {
      override fun cancel() {
        ******@****.***()
      }

      override val sink =

   * and duplex calls where the timeout only applies to the initial setup.
   */
  fun timeoutEarlyExit() {
    check(!timeoutEarlyExit)
    timeoutEarlyExit = true
    timeout.exit()
  }

  fun upgradeToSocket() {
    timeoutEarlyExit()

    withLock {
      check(exchange != null)
      check(!socketSinkOpen && !socketSourceOpen)
      check(!requestBodyOpen)
      check(responseBodyOpen)