Download progress with ktor and flow

Downloader.kt

sealed class DownloadResult {
  data class Progress(val progress: Int): DownloadResult()
  object Success: DownloadResult()
  data class Error(val message: String): DownloadResult()
}

suspend fun downloadFile(downloadedFile: File, url: String) = flow {
  emit(Downloadresult.Progress(0))
  val fos = downloadedFile.outputStream()
  
  val bufSize = 4096
  val buffer = ByteArray(bufSize)
  var total = 0
  
  val bytes = client.get<ByteReadChannel>(url)
  
  while (true) {
    val result = bytes.readAvailable(buffer, 0, bufSize)
    if (result == -1) {
      break
    }
    total += result
    val progress = (total * 100 / fileSize).toInt()
    emit(DownloadResult.Progress(progress))
    fos.write(buffer)
    fos.close()
    emit(DownloadResult.Success)
  }
}.distinctUntilChanged().flowOn(Dispatchers.IO)

val fos = file.outputStream() -> in this 'file' where it comes from or could u tell how to use this

val fos = file.outputStream() -> in this 'file' where it comes from or could u tell how to use this
Sorry @san-sk, I wrote wrong name, 'file' is the file which you store download resource, I updated name to 'downloadFile' for clearer meaning