https://twitter.com/luke_pighetti/status/1666235640265027585

proposal.dart

// we need this in core dart so all these serialization packages can use it
// this enables generalized solutions for storage, messaging, tasks, etc
abstract interface class JsonCoder<T> {
  String toJson(T payload);
  T fromJson(String payload);
}

// then we can create generalized packages for things like storage
/// ```dart
/// final box1 = Storage(MyFreezedDataClass.coder);
/// final box2 = Storage(MyBuiltValue.coder);
/// final box3 = Storage(MyDartMappable.coder);
/// final box4 = Storage(MyHandCrafted.coder);
/// ```
class BasedStorage {
  void store<T>(String key, JsonCoder<T> object) {
    ///...
  }

  T fetch<T extends JsonCoder>(String key) {
    /// ...
  }
}

// developers can create simple data classes using any serialization package
class MyDataClass {
  final String foo;
  final String bar;
  MyDataClass(this.foo, this.bar);

  // generated, added by hand
  static final coder = MyDataClassJsonCoder();
}

// generated by existing serialization package implementing JsonCoder
class MyDataClassJsonCoder extends JsonCoder<MyDataClass> {
  @override
  MyDataClass fromJson(String payload) {
    final map = jsonDecode(payload);
    return MyDataClass(map['foo'], map['bar']);
  }

  @override
  String toJson(MyDataClass payload) {
    final map = {'foo': payload.foo, 'bar': payload.bar};
    return jsonEncode(map);
  }
}

z_maybe.dart

// or maybe this??
class JsonCoder<T> extends Codec<String, T> {
  @override
  Converter<T, String> get decoder => throw UnimplementedError();

  @override
  Converter<String, T> get encoder => throw UnimplementedError();
}