anchor.diff:      committed_seq,
       current_through_seq,
       seqs_in_progress = [],
  -    highest_seq_done = ?LOWEST_SEQ,
  +    highest_seq_done = {0, ?LOWEST_SEQ},
       source_log,
       target_log,
       rep_starttime,
  
positive.code:     [SourceLog, TargetLog] = find_replication_logs([Source, Target], Rep),
  
      {StartSeq0, History} = compare_replication_logs(SourceLog, TargetLog),
      StartSeq = get_value(since_seq, Options, StartSeq0),
      #doc{body={CheckpointHistory}} = SourceLog,
      State = #rep_state{
          rep_details = Rep,
  
negative.code:         target = Target,
          source_name = SourceName,
          target_name = TargetName,
          start_seq = {_Ts, StartSeq},
          source_seq = SourceCurSeq
      } = State = init_state(Rep),
  
  