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 =

              .body(
                UnreadableResponseBody(
                  response.body.contentType(),
                  response.body.contentLength(),
                ),
              ).socket(exchange.upgradeToSocket())
              .build()
          }

          // This is not an upgrade response.
          else -> {
            val responseBody = exchange.openResponseBody(response)
            response