private fun newUnknownLengthSource(url: HttpUrl): Source {
    check(state == STATE_OPEN_RESPONSE_BODY) { "state: $state" }
    state = STATE_READING_RESPONSE_BODY
    carrier.noNewExchanges()
    return UnknownLengthSource(url)
  }

  /**
   * Sets the delegate of `timeout` to [Timeout.NONE] and resets its underlying timeout
   * to the default configuration. Use this to avoid unexpected sharing of timeouts between pooled