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

        $this->setLastModified(DateTime::createFromFormat('U', (string) $this->file->getMTime()));

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

        $this->setLastModified(DateTime::createFromFormat('U', (string) $this->file->getMTime()));

        return $this;
    }
自动设置最后修改时间.

@return $this