anchor.diff:      'method': method,
       'enabled': debugPaintSizeEnabled
     });
  -  return new Future.value(new ServiceExtensionResponse.result(result));
  +  return new Future<ServiceExtensionResponse>.value(new ServiceExtensionResponse.result(result));
   }
   
   /// Manipulate the scheduler's [timeDilation] field.
  -Future<ServiceExtensionResponse> _timeDilation(String method, Map parameters) {
  +Future<ServiceExtensionResponse> _timeDilation(String method, Map<String, dynamic> parameters) {
     if (parameters.containsKey('timeDilation')) {
       // TODO: Workaround for https://github.com/dart-lang/sdk/issues/25208.
       dynamic param = parameters['timeDilation'];
  
positive.code:   if (_extensionsInitialized)
      return;
  
    registerExtension('flutter', _flutter);
    // TODO: Expose debugDumpApp().
    // TODO: Expose StatisticsOverlay.
    registerExtension('flutter.debugPaint', _debugPaint);
    registerExtension('flutter.timeDilation', _timeDilation);
  
    _extensionsInitialized = true;
  
    // Emit an info level log message; this tells the debugger that the Flutter
    // service extensions are registered.
    log('Flutter initialized', name: 'flutter', level: 800);
  }
  
  /// Just respond to the request. Clients can use the existence of this call to
  /// know that the debug client is a Flutter app.
  Future<ServiceExtensionResponse> _flutter(String method, Map parameters) {
    String result = JSON.encode({ 'type': '_extensionType', 'method': method });
    return new Future.value(new ServiceExtensionResponse.result(result));
  }
  
  /// Toggle the [debugPaintSizeEnabled] setting.
  Future<ServiceExtensionResponse> _debugPaint(String method, Map parameters) {
    if (parameters.containsKey('enabled')) {
      // TODO: This is a work around for a VM bug: sdk/25208 - all params are
      // coerced to strings.
      // bool enabled = parameters['enabled'] == true;
      debugPaintSizeEnabled = parameters['enabled'].toString() == 'true';
      // TODO: How to cause a redraw?
    }
  
    String result = JSON.encode({
  
negative.code: import 'dart:ui' as ui;
  
  import 'package:flutter/painting.dart';
  import 'package:flutter/rendering.dart';
  import 'package:flutter/scheduler.dart';
  import 'package:vector_math/vector_math_64.dart';
  
  