anchor.diff:        .get();
   
     // Find an existing change group with a blamelist that intersects this change.
  -   final startIndex = buildInfo['startIndex'];
  -   final endIndex = buildInfo['endIndex'];
  +  final startIndex = buildInfo['startIndex'];
  +  final endIndex = buildInfo['endIndex'];
   
     bool blamelistIncludesChange(DocumentSnapshot groupDocument) {
       var group = groupDocument.data;
  
positive.code:   final documentRef = firestore.document('builds/$builder:$endIndex');
    final record = await documentRef.get();
    if (!record.exists) {
      await documentRef
          .setData(DocumentData.fromMap(
          {'builder': builder, 'build_number': buildNumber, 'index': endIndex}));
      info('Created build record: '
          'builder: $builder, build_number: $buildNumber, index: $endIndex');
  
    } else if (record.data.getInt('index') != endIndex) {
        error('Build $buildNumber of $builder had commit index ${record.data.getInt('index')},'
            'should be $endIndex.');
    }
   return {"startIndex": startIndex, "endIndex": endIndex};
  }
  
  Future<void> storeChange(Map<String, dynamic> change,
  
negative.code:   final stats = Statistics();
    var buildInfo = await storeBuildInfo(results, stats);
    await Future.forEach(results.where(isChangedResult),
        (result) => storeChange(result, buildInfo, stats));
    stats.report();
  }
  
  