src/Leevel/Http/Response.php
public function setNotModified(): IResponse
    {
        if ($this->checkFlowControl()) {
            return $this;
        }

        $this->setStatusCode(304, self::$statusTexts[304]);

        return $this;
    }
public function setNotModified(): IResponse
    {
        if ($this->checkFlowControl()) {
            return $this;
        }

        $this->setStatusCode(304, self::$statusTexts[304]);

        return $this;
    }
设置响应未修改.

@return $this