toJson method Null safety

Implementation

@override
Map<String, dynamic> toJson() {
  final json = super.toJson();
  json['type'] = type;
  json.addAll({
    'breakpointNumber': breakpointNumber,
    'enabled': enabled,
    'resolved': resolved,
    'location': location?.toJson(),
  });
  _setIfNotNull(
      json, 'isSyntheticAsyncContinuation', isSyntheticAsyncContinuation);
  return json;
}