anchor.diff:  import 'dart:async';
   import 'dart:convert';
   import 'dart:io';
  +import 'dart:math' as math;
   
   import 'package:path/path.dart' as path;
   
  
positive.code:            && content.endsWith(']: 0x1'))
           return null;
  
        _lastWasFiltered = false;
  
        if (category == 'Runner')
          return content;
        return '$category: $content';
      }
      match = _lastMessageRegex.matchAsPrefix(string);
      if (match != null && !_lastWasFiltered)
        return '(${match.group(1)})';
      return string;
    }
  
    void _onDeviceLine(String line) {
      String filteredLine = _filterDeviceLine(line);
      if (filteredLine == null)
        return;
      _linesController.add(filteredLine);
    }
  
    String _filterSystemLog(String string) {
  
negative.code:   final IOSSimulator device;
  
    StreamController<String> _linesController;
  
    // We log from two files: the device and the system log.
    Process _deviceProcess;
  