anchor.diff:          'gc': isGC,
         };
   
  -  @JsonKey(name: 'timestamp')
     final int timestamp;
   
  -  @JsonKey(name: 'rss')
     final int rss;
   
  -  @JsonKey(name: 'capacity')
     final int capacity;
   
  -  @JsonKey(name: 'used')
     final int used;
   
  -  @JsonKey(name: 'external')
     final int external;
   
  -  @JsonKey(name: 'gc')
     final bool isGC;
   }
   
  
positive.code: import 'dart:async';
  import 'dart:math' as math;
  
  import 'package:json_annotation/json_annotation.dart';
  import 'package:vm_service/vm_service.dart';
  
  import '../globals.dart';
  
negative.code:   }
  }
  
  class HeapSample {
    HeapSample(
      this.timestamp,
  