例えばこれを

  openCamera(id).use { dev ->
    dev.video().use { vidIn ->
      File(dstPath).outputStream().use { output ->
        val vidOut = videoWriter(output)
        vidIn.eachFrame { frame ->
          filter.write(frame, vidOut)
          return checkContinue()
        }
      }
    }
  }

このように

  use val dev = cameraOpen(id)
  use val vidIn = dev.video()
  use val output = File(dstPath).outputStream()
  val vidOut = videoWriter(output)
  vidIn.eachFrame { frame ->
    filter.write(frame, vidOut)
    return checkContinue()
  }