src/Application/SimpleApplication.php
public function request(RequestInterface $request = null) : RequestInterface
    {
        if ($request){
            $this->request = $request;
        }
        if (!$this->request){
            $this->request = new NullRequest;
        }
        return $this->request;
    }
public function request(RequestInterface $request = null) : RequestInterface
    {
        if ($request){
            $this->request = $request;
        }
        if (!$this->request){
            $this->request = new NullRequest;
        }
        return $this->request;
    }
Set/get request

@param RequestInterface $request

@return RequestInterface