await (Function) fn(); for non async fns

main.dart

Future<String> asyncFunctionn() async {
  return Future<String>.delayed(
    const Duration(milliseconds: 10), 
    () => "Async function",
  );
}

String syncFunction() {
  return "Sync function";
}

void run(Function fn) async {
  print(await fn());
}


void main() async {
  await run(asyncFunctionn);
  run(syncFunction);
}