anchor.diff:        var stopwatch = new Stopwatch()..start();
   
         // Initialize query specific objects
  -      TestMapper mapper = new TestMapper(new SevereLogMapper(), file.path);
  +      TestMapper mapper = new TestMapper(new CompletionMapper(), file.path);
   
         // Extraction
         await mapper.init({}, (String key, value) {
  
positive.code: import 'package:sintr_worker_lib/instrumentation_transformer.dart';
  import 'package:sintr_worker_lib/query.dart';
  import 'package:sintr_worker_lib/query/completion_metrics.dart';
  import 'package:sintr_worker_lib/query/severe_log.dart';
  import 'package:sintr_worker_lib/session_info.dart';
  
  main(List<String> args) async {
  
negative.code:           .openRead()
            .transform(UTF8.decoder)
            .transform(new LineSplitter())
            .transform(new LogItemTransformer())
            .handleError((e, s) {
          ++mapper.readFailureCount;
          print("Error reading line\n${trim300(e.toString())}\n$s");
  