injector<S>  method 
Holds a reference to every registered callback when using
Get.lazyPut()
Implementation
// static final Map<String, _Lazy> _factory = {};
void injector<S>(
  InjectorBuilderCallback<S> fn, {
  String? tag,
  bool fenix = false,
  //  bool permanent = false,
}) {
  lazyPut(
    () => fn(this),
    tag: tag,
    fenix: fenix,
    // permanent: permanent,
  );
}