下面是我在lumen中的路线。$app->get('contact-us/{msg?}',function(){echoInput::all();});它抛出以下错误。atApplication->handleDispatcherResponse(array('0'))inApplication.phpline1184atApplication->Laravel\Lumen\{closure}()inApplication.phpline1414atApplication->sendThroughPipeline(array(),object(Closure))inApplicatio