anchor.diff:      NewState = State#state{handle=Handle},
       {noreply, NewState};
   
  -handle_cast(close, State) when State#state.dir_monitor =/= none ->
  +handle_cast(close, State) ->
       #state{
           torrent=Torrent,
           handle=Handle,
  
positive.code: -record(state, {
      torrent :: torrent_id(),
      handle=closed :: closed | file:io_device(),
      relpath :: file_path(),
      fullpath :: file_path(),
      dir_monitor=none :: none | reference(),
      await_ref=none :: none | reference()}).
  
  
  -spec start_link(torrent_id(), file_path(), file_path()) -> {'ok', pid()}.
  
negative.code:     ok = file:pwrite(Handle, Offset, Chunk),
      {reply, ok, State}.
  
  handle_cast(open, State) ->
      #state{
          torrent=Torrent,
          handle=closed,
  