anchor.diff:    }
   
     static get tsvHeader => 
  -    'Number\tTitle\tURL\tPriority\tAuthor\tCreated At\tAssignees\tMilestone\tDue On\tClosed At';
  +    'Number\tTitle\tURL\tPriority\tAuthor\tCreated At\tAssignees\tOriginal Milestone\tCurrent Milestone\tDue On\tClosed At';
   
     // Top level entities like Issue and PR must TSV, because their fields CSV,
     // and Google Sheets only takes mixed CSV/TSV records with TSV being the containing
     // record format.
     String toTsv() {
       String milestoneHistory = '';
  -    if (timeline != null) timeline.milestoneTimeline().forEach((milestone) =>
  -      milestoneHistory = '${milestoneHistory},${milestone}'
  +    if (timeline != null) timeline.milestoneTimeline.forEach((milestone) =>
  +      milestoneHistory = milestone == null ? milestoneHistory : '${milestoneHistory},${milestone.title}'
       );
       if (milestoneHistory.length > 0) milestoneHistory = milestoneHistory.substring(1);
       if (milestoneHistory.length == 0) milestoneHistory = _milestone ?? '';
  +
  +    var originalMilestone;
  +    if (_timeline == null) originalMilestone = '';
  +    if (_timeline.originalMilestone == null) originalMilestone = ''; else _timeline.originalMilestone.title;
  +    var currentMilestone = _milestone == null ? '' : _milestone.title;
  +    var dueOn = _milestone == null ? '' : _milestone.dueOn.toString();
  +
   
       String tsv = '';
       tsv = '${tsv}${_number}';
  
positive.code:   }
  
    static get tsvHeader => 
      'Number\tTitle\tURL\tPriority\tAuthor\tCreated At\tMerged?\tAssignees\tMilestone\tDue On\tMerged At\tClosed At';
  
    // Top level entities like Issue and PR must TSV, because their fields CSV,
    // and Google Sheets only takes mixed CSV/TSV records with TSV being the containing
    // record format.
    String toTsv() {
      String milestoneHistory = '';
      if (timeline != null) timeline.milestoneTimeline().forEach((milestone) =>
        milestoneHistory = '${milestoneHistory},${milestone}'
      );
      if (milestoneHistory.length > 0) milestoneHistory = milestoneHistory.substring(1);
      if (milestoneHistory.length == 0) milestoneHistory = _milestone ?? '';
  
      String tsv = '';
      tsv = '${tsv}${_number}';
  
negative.code:     } else {
        tsv = '${tsv}\t';
      }
     tsv = '${tsv}\t${originalMilestone}';
      tsv = '${tsv}\t${currentMilestone}';
      tsv = '${tsv}\t${dueOn}';
      tsv = _closedAt == null ? '${tsv}\t': '${tsv}\t${_closedAt}';
  
      return tsv;
  