collect_engine_routes

# File railties/lib/rails/application/route_inspector.rb, line 48
      def collect_engine_routes(name, rack_app)
        return unless rack_app && rack_app.respond_to?(:routes)
        return if @engines[name]

        routes = rack_app.routes
        if routes.is_a?(ActionDispatch::Routing::RouteSet)
          @engines[name] = collect_routes(routes.routes)
        end
      end