Set X-Transmission-Session-Id when return code == 409

TransmissionClient.scala

  // If Code == 409, Set X-Transmission-Session-Id and retry.
  def httpX[T](x: Handler[T]): HttpPackage[T] = {
    val hand = x.copy(request = x.request <:< Map("X-Transmission-Session-Id" -> sessId))

    var is409: Boolean = false
    val r = http.x(hand.copy(
      block = { (code, res, ent) =>
      if (code != 409)
        hand.block(code, res, ent)
      else {
        val st = Map.empty[String, Set[String]].withDefaultValue(Set.empty)
        sessId = ((st /: res.getAllHeaders()) { (m, h) =>
          m + (h.getName -> (m(h.getName) + h.getValue))
        }).get("X-Transmission-Session-Id").get.head
        is409 = true
        hand.block(code, res, ent)
      }
    }))

    if (!is409)
      r
    else
      httpX(x)
  }