src/Application.php
public function run($runner = Relay::class)
    {
        $this->configuration->apply($this->injector);

        return $this->injector
            ->share($this->middleware)
            ->prepare(Directory::class, $this->routing)
            ->execute($runner);
    }
public function run($runner = Relay::class)
    {
        $this->configuration->apply($this->injector);

        return $this->injector
            ->share($this->middleware)
            ->prepare(Directory::class, $this->routing)
            ->execute($runner);
    }
Run the application

@param string $runner

@return \Psr\Http\Message\ResponseInterface