为什么每次请求都执行两次？fmt.Println("请求:", (i))会打印两次

package main

import (
    "net/http"
    "fmt"
    "strconv"
)

var writera http.ResponseWriter
var i int64 = 0

func main() {
    http.HandleFunc("/", func(writer http.ResponseWriter,
        request *http.Request) {
        fmt.Println("请求:", (i))
        i++
        writera = writer
        name := request.FormValue("name")

        outHtml("name=" + name)
    })

    port2 := 82
    fmt.Println("http://localhost:" + strconv.Itoa(port2))
    http.ListenAndServe(":"+strconv.Itoa(port2), nil)
}
func outHtml(c ...interface{}) {
    for _, v := range c {
        fmt.Fprintln(writera, v)
        fmt.Println()
    }
}