var callDone = false
    withLock {
      if (expectMoreExchanges) {
        expectMoreExchanges = false
        callDone = !requestBodyOpen && !responseBodyOpen && !socketSinkOpen && !socketSourceOpen
      }
    }

    if (callDone) {
      return callDone(e)
    }

    return e
  }

  /**
   * Complete this call. This should be called once these properties are all false: