sendResponse("server says goodbye\n")
          exhaustResponse()
          exhaustRequest()
        }
    server.enqueue(socketHandler.upgradeResponse())

    client
      .newCall(
        upgradeRequest(),
      ).execute()
      .use { response ->
        assertThat(response.code).isEqualTo(HTTP_SWITCHING_PROTOCOLS)
        val socket = response.socket!!
        socket.sink.buffer().use { sink ->

    val message6 = message2 + message2
    client.send(message6)
    serverListener.assertTextMessage(message6)
    closeWebSockets(client, server)
    val upgradeRequest = webServer.takeRequest()
    assertThat(upgradeRequest.headers["Sec-WebSocket-Extensions"])
      .isEqualTo("permessage-deflate")
  }

  @Throws(Exception::class)
  private fun extensionNegotiationFailure(extensionsHeader: String) {