有日志(stdout or file) qps 4k，没日志 qps 10w. why?

# 没有use(logger)
# wrk -c2000 -d10s -t6 http://localhost:8000/
Running 10s test @ http://localhost:8000/
  6 threads and 2000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     2.50ms    3.47ms  57.16ms   88.65%
    Req/Sec    15.91k     3.05k   33.29k    72.17%
  950515 requests in 10.03s, 0.93GB read
  Socket errors: connect 1753, read 97, write 0, timeout 0
Requests/sec:  94757.42
Transfer/sec:     94.80MB

# use(logger)
# wrk -c2000 -d10s -t6 http://localhost:8000/
Running 10s test @ http://localhost:8000/
  6 threads and 2000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   378.75ms  118.71ms   1.51s    84.82%
    Req/Sec   106.91     46.29   282.00     64.64%
  6369 requests in 10.06s, 6.37MB read
  Socket errors: connect 1753, read 86, write 0, timeout 0
Requests/sec:    632.87
Transfer/sec:    648.32KB

func main() {
	app := echo.New()
	app.HideBanner = true

	app.Use(middleware.Logger())# <- 就这里
	app.Use(middleware.Recover())
	app.Use(middleware.RequestID())

	app.GET("/", func(c echo.Context) error {
		return c.Render(200, "content/index", echo.Map{})
	})
        app.Start(":8000")
}