anchor.diff:  
       if (i % 1000 == 0 && i > 0) print("INC: $i fixes");
       lastOffset = i;
  -    if (_SERVER_BASED_CALL) await server.fixesGet(source: src, offset: i);
  -    else await wrapper.getFixes(src, i);
  -
  +    if (_SERVER_BASED_CALL) {
  +      await withTimeOut(server.fixesGet(source: src, offset: i));
  +    } else {
  +      await withTimeOut(wrapper.getFixes(src, i));
  +    }
       if (_PERF_DUMP) print ("PERF: FIXES: ${sw2.elapsedMilliseconds}");
     }
     return sw.elapsedMilliseconds / src.length;
  
positive.code:   Stopwatch sw = new Stopwatch()..start();
  
    lastOffset = null;
    if (_SERVER_BASED_CALL) await server.analyzeGet(source: src);
    else await analyzer.analyze(src);
  
    if (_PERF_DUMP) print ("PERF: ANALYSIS: ${sw.elapsedMilliseconds}");
    return sw.elapsedMilliseconds;
  
negative.code:   Stopwatch sw = new Stopwatch()..start();
    int i = 0;
    lastOffset = i;
    await withTimeOut(server.formatGet(source: src, offset: i));
    return sw.elapsedMilliseconds;
  }
  
  Future withTimeOut(Future f) {
    return f.timeout(new Duration (seconds: 30));
  }
  
  String mutate(String src) {
  