anchor.diff:      From ! Result,
       exit(normal).
   
  -handle_append(_Prefix, <<>>, _Csum, _Extra, _FluName) ->
  +handle_append(_Prefix, <<>>, _Csum, _Extra, _FluName, _EpochId) ->
       {error, bad_arg};
  -handle_append(Prefix, Chunk, Csum, Extra, FluName) ->
  -    Res = machi_flu_filename_mgr:find_or_make_filename_from_prefix(FluName, {prefix, Prefix}),
  +handle_append(Prefix, Chunk, Csum, Extra, FluName, EpochId) ->
  +    Res = machi_flu_filename_mgr:find_or_make_filename_from_prefix(FluName, EpochId, {prefix, Prefix}),
       case Res of
           {file, F} ->
               {ok, Pid} = machi_flu_metadata_mgr:start_proxy_pid(FluName, {file, F}),
  
positive.code:             {error, bad_arg}
      end.
  
  append_server_dispatch(From, Prefix, Chunk, CSum, Extra, FluName) ->
      Result = case handle_append(Prefix, Chunk, CSum, Extra, FluName) of
          {ok, File, Offset} ->
              {assignment, Offset, File};
          Other ->
  
negative.code:             case OldEpochId == EpochID of
                  true ->
                      spawn(fun() -> 
                          append_server_dispatch(From, Prefix, Chunk, CSum, Extra, FluName, EpochID) 
                      end);
                  false ->
                      From ! {error, bad_epoch}
  