mmm.scala

protected def interleaveDevices(devices: List[Device], busId: EventBusId, msgFactory: Device ⇒ ApiWebRTCSignaling): Future[Unit] = {
  (devices |@| devices).tupled.filter(d => d._1.deviceId != d._2.deviceId).foldLeft(FastFuture.successful[Unit](())) {
    case (acc, (left, right)) =>
      acc *> postFromThisDevice(busId, left, msgFactory(right).toByteArray) *> postFromThisDevice(busId, right, msgFactory(left).toByteArray)
  }
}