Generated dart code for JSON wire format is too proprietary!

[chipweinberger]

I hope this does not fall on deaf ears. Thanks for working on Dart support for protobufs!

When using JSON as the wire-format, why does the generated Dart code use so much protobuf specific code like GeneratedMessage, PbList, ExtensionRegistry, etc? JSON deserialization is already part of the Dart standard library, doesn't it seem kinda unnecessary to generate so much non standard code?

I understand JSON is probably not the focus of this protobuf library, but there are good use cases! For example, trying to remove the protobuf runtime dependency in Flutter Blue Plus. See: boskokg/flutter_blue_plus#236

It would be awesome if this was improved.

syntax = "proto3";
message User {
  int64 id = 1;
  string name = 2;
  string email = 3;
}

// Generated by the protocol buffer compiler. DO NOT EDIT!
// source: user.proto

import 'dart:core' show int, bool, double, String, List, override;
import 'package:protobuf/protobuf.dart';

class User extends GeneratedMessage {
  static final BuilderInfo _i = BuilderInfo('User')
    ..aInt64(1, 'id')
    ..aOS(2, 'name')
    ..aOS(3, 'email')
    ..hasRequiredFields = false;

  User() : super();
  User.fromBuffer(List<int> i,
      [ExtensionRegistry r = ExtensionRegistry.EMPTY])
      : super.fromBuffer(i, r);
  User.fromJson(String i, [ExtensionRegistry r = ExtensionRegistry.EMPTY])
      : super.fromJson(i, r);
  User clone() => User()..mergeFromMessage(this);
  BuilderInfo get info_ => _i;
  static User create() => User();
  static PbList<User> createRepeated() => PbList<User>();
  static User getDefault() {
    if (_defaultInstance == null) _defaultInstance = User._();
    return _defaultInstance;
  }

  static User _defaultInstance;
  static void $checkItem(User v) {
    if (v is! User) checkItemFailed(v, 'User');
  }

  int get id => $_getI64(0);
  set id(int v) {
    $_setInt64(0, v);
  }

  bool hasId() => $_has(0);
  void clearId() => clearField(1);

  String get name => $_getS(1, '');
  set name(String v) {
    $_setString(1, v);
  }

  bool hasName() => $_has(1);
  void clearName() => clearField(2);

  String get email => $_getS(2, '');
  set email(String v) {
    $_setString(2, v);
  }

  bool hasEmail() => $_has(2);
  void clearEmail() => clearField(3);
}