fil/docs/snippets/dart/plugins/plugin_validator.md

import 'package:kreuzberg/kreuzberg.dart';

Future<void> main() async {
  // A Dart implementation of the `Validator` trait that gates on MIME type
  // cannot be plugged into the global validator registry.
  // `Kreuzberg.registerValidator(impl)` exists, but its
  // `createValidatorDartImpl` factory requires opaque `BoxFn*` closure
  // values whose constructors are not surfaced through
  // flutter_rust_bridge.
  //
  // Implement the validator in Rust and register it via `register_validator`
  // in a Rust shim crate.
}