anchor.diff:    "Map": () => new StandardMapInterface(),
   };
   
  -int times = 10;
  +int times = 4;
   
   void main() {
  +
     var config = [
      {'name': 'Write',
       'creator': ((sample, factory) => (new WriteBenchmark(sample, factory))),
  
positive.code:       for (String name in interfaces.keys) {
          var _dev = 2*(res[name]*dev['Map']+res['Map']*dev[name])/res['Map']/res['Map']/sqrt(times);
          print('${mode} ${name} sample ${sample}: ${res[name]/res['Map']} '+
                '+- ${_dev} (${res[name]} us)');
        }
      }
    });
  
negative.code:       for (int i=0; i<times; i++){
          for (String name in interfaces.keys) {
            var meas = creator(sample, interfaces[name]).measure();
            meas /= 1000; // we want milliseconds
            meas /= 10; //to compensate for tenfold error in benchmark harness
            res[name] += meas;
            dev[name] += meas*meas;
          }
  