Const constructor

main.dart

import 'dart:typed_data';

const BAR = Foo(
  a: true,
  b: 1234,
  c: C(
    $unknownData: null,
    d: "abcd",
  ));

void main() {
  print ("a: ${BAR.a}");
  print ("b: ${BAR.b}");
  print ("c.d: ${BAR.c.d}");
}

// Everything below is existing fildgen output.
class Foo {
  const Foo({
    required this.a,
    required this.b,
    required this.c,
  });
  
  final bool a;
  final int b;
  final C c;
}

class C {
  const C({
    this.$unknownData,
    this.d,
  });

  @override
  final Map<int, UnknownRawData>? $unknownData;
  final String? d;
}

class UnknownRawData {
  UnknownRawData(this.data, this.handles);
  Uint8List data;
  List<int> handles;
}