anchor.diff:  // BSD-style license that can be found in the LICENSE file.
   
   import 'dart:async';
  -import 'dart:io';
  +import 'dart:developer';
   import 'dart:isolate';
   import 'dart:math';
   
   import 'package:meta/meta.dart';
   
   import 'package:compiler/src/dart2js.dart' as dart2js_main;
  +import 'package:vm_service/vm_service.dart' as vm_service;
  +import 'package:vm_service/vm_service_io.dart' as vm_service_io;
   
   class SpawnLatencyAndMemory {
  -  SpawnLatencyAndMemory(this.name);
  +  SpawnLatencyAndMemory(this.name, this.wsUri, this.groupRefId);
   
     Future<ResultMessageLatencyAndMemory> run() async {
       final completerResult = Completer();
  
positive.code:           timeRunningCodeUs.difference(start.spawned).inMicroseconds,
        timeToFinishRunningCodeUs:
            timeFinishRunningCodeUs.difference(start.spawned).inMicroseconds,
        deltaRss: ProcessInfo.currentRss - start.rss));
  }
  
  Future<void> main() async {
    await SpawnLatencyAndMemory("IsolateSpawn.Dart2JS").report();
  }
  
negative.code:     this.toStartRunningCodeUs,
      this.toFinishRunningCodeUs,
      this.toExitUs,
      this.deltaHeap,
    );
  
    String toString() => """$toAfterIsolateSpawnUs
  $toStartRunningCodeUs
  $toFinishRunningCodeUs
  $toExitUs
  $deltaHeap""";
  
    final Metric toAfterIsolateSpawnUs;
    final Metric toStartRunningCodeUs;
    final Metric toFinishRunningCodeUs;
    final Metric toExitUs;
    final Metric deltaHeap;
  }
  
  Future<void> isolateCompiler(StartMessageLatencyAndMemory start) async {
  