anchor.diff:  
   handle_info({writer_checkpoint, SourceSeq}, #state{committed_seq=N} = State)
           when SourceSeq > N ->
  -    ?LOG_DEBUG("SourceSeq ~p N ~p", [SourceSeq, N]),
       MissingRevs = State#state.missing_revs,
       ok = gen_server:cast(MissingRevs, {update_committed_seq, SourceSeq}),
       couch_task_status:update("W Processed source update #~p", [SourceSeq]),
  
positive.code: make_replication_id({Props}, UserCtx) ->
      %% funky algorithm to preserve backwards compatibility
      {ok, HostName} = inet:gethostname(),
      Src = get_rep_endpoint(UserCtx, proplists:get_value(<<"source">>, Props)),
      Tgt = get_rep_endpoint(UserCtx, proplists:get_value(<<"target">>, Props)),    
      couch_util:to_hex(erlang:md5(term_to_binary([HostName, Src, Tgt]))).
  
negative.code:         stats = Stats
      } = State,
      ?LOG_INFO("recording a checkpoint at source update_seq ~p", [NewSeqNum]),
      RecordSeqNum = case commit_to_both(Source, Target, NewSeqNum) of
      {SrcInstanceStartTime, TgtInstanceStartTime} ->
          NewSeqNum;
      _Else ->
  