https://blog.gongquiz.com/2022/11/23/%ed%94%8c%eb%9f%ac%ec%89%ac-%eb%a8%b8%eb%a6%acflush-head-%eb%a6%ac%eb%b2%b3%ec%9e%91%ec%97%85%ec%9d%84-%ed%95%a0-%eb%95%8c-%eb%81%9d%ea%b1%b0%eb%a6%ac-%eb%b0%8f-%eb%a6%ac%eb%b2%b3%ea%b0%84%ea%b2%a9/