anchor.diff:      %% TODO: Do anything with PKey?
       try
           TaggedCSum = check_or_make_tagged_checksum(CSum_tag, Client_CSum,Chunk),
  -        FluName ! {seq_append, self(), Prefix, Chunk, TaggedCSum,
  -                   ChunkExtra, EpochID},
  +        R = {seq_append, self(), Prefix, Chunk, TaggedCSum, ChunkExtra, EpochID},
  +        FluName ! R,
           receive
               {assignment, Offset, File} ->
                   Size = iolist_size(Chunk),
  
positive.code: handle_append(_Prefix, <<>>, _Csum, _Extra, _FluName) ->
      {error, bad_arg};
  handle_append(Prefix, Chunk, Csum, Extra, FluName) ->
      case machi_flu_filename_mgr:find_or_make_filename_from_prefix({prefix, Prefix}) of
          {file, F} ->
              {ok, Pid} = machi_flu_metadata_mgr:start_proxy_pid(FluName, {file, F}),
              {Tag, Csum} = machi_util:unmake_tagged_csum(Csum),
              Meta = [{client_csum_tag, Tag}, {client_csum, Csum}],
              machi_file_proxy:append(Pid, Meta, Extra, Chunk);
          Error ->
              Error
  
negative.code:     case machi_flu_metadata_mgr:lookup_proxy_pid(FluName, {file, File}) of
          undefined ->
              ok;
          Pid ->
            machi_file_proxy:sync(Pid, csum)
      end.
  
  