trait Cake
    extends OrderedBlockFileDSModule[IO]
    with NettySyncModule[IO]
    with VanillaServer[IO]
    with IndexModuleImpl[IO] {

  override val M = IO.ioMonad

  def main(): IO[RRUnit] = for {
    syncer <- Syncer(listener)
    tracker = syncer.tracker

    data <- readDataFromUser
    chunks = splitIntoChunks(data, Config.BlockSize)
    blocks <- chunks traverse balloc
    extent <- store(blocks)
    _ <- extent.blocks traverse { block => tracker.publishBlock(block.hash, true) }
    _ <- syncer.run.run
  }

  def listener: StepT[Block, IO, A] = {
    StepT.Cont { in =>
      in.fold(
        el = { block => putStrLn(block.hash) },
        ....)
    }
  }
}