How to use the injection-js.ReflectiveInjector.fromResolvedProviders function in injection-js

// find matching route, fabricating if necessary
    let route = this.matchImpl(paths, rpaths, method, parent, routes, params);
    // we always need a handler
    if (!route.handler) {
      if (route.children)
        route.handler = NotFound;
      else route.handler = route.redirectTo? RedirectTo : StatusCode200;
    }
    // create an injector
    if (!route.injector) {
      const providers = (route.services || []).concat(route.middlewares || []);
      providers.push(route.handler);
      const resolved = ReflectiveInjector.resolve(providers);
      if (parent)
        route.injector = parent.injector.createChildFromResolved(resolved);
      else route.injector = ReflectiveInjector.fromResolvedProviders(resolved);
    }
    // look to the children
    if (route.children && (paths.length > rpaths.length))
      route = this.match(paths.slice(rpaths.length), method, route, route.children, params);
    return route;
  }

return await Promise.all(this.providers).then(async (providers) => {
      const resolvedProviders = ReflectiveInjector.resolve(CORE_PROVIDERS(this.options).concat(providers));
      const injector = ReflectiveInjector.fromResolvedProviders(resolvedProviders);
      const dispatcher = injector.get(AsyncEventDispatcher);
      resolvedProviders.forEach((provider: ResolvedReflectiveProvider) => {
        const service = injector.get(provider.key.token);
        this.resolveInjectorAwareService(service, injector);
        this.resolveEventListeners(service, dispatcher);
      });
      const bootstrapEvent = new BootstrapEvent(injector, resolvedProviders);
      await dispatcher.dispatch(ApplicationEvents.BOOTSTRAP, bootstrapEvent);
      injector.get(Kernel).initialize();
      return injector;
    });
  }