anchor.diff:  
   import 'dart:io';
   import 'dart:async';
  +import 'dart:convert';
   import 'package:path/path.dart' as path;
   
   class AnalyzerConfig {
  
positive.code: 
    AnalyzerConfig(this.directory);
  
    String get dartVMPath => path.join(sdkPath, 'bin', 'dart');
  
    String getSnapshotPath(String snapshotName) =>
  
negative.code: class Analyzer {
    final AnalyzerConfig config;
  
    Process _process;
  
    StreamSubscription<String> _inStreamSub;
  
    Analyzer(this.config);
  
    bool get isRunning => _process != null;
  
    Future<Null> start() async {
      if (isRunning) {
        throw new Exception("Analyzer already running!");
      }
      _process = await _createProcess(config);
      _inStreamSub = _process.stdout
          .transform(UTF8.encoder)
          .transform(new LineSplitter())
          .listen(_processInMsg);
      //TODO connect writer
    }
  
    /// Restarts, or starts, the analysis server process.
  