go - HandleFunc being called twice

Question

I am following a simple web server example in Go.

I inserted a log statement so that the resulting code looks like below:

package main

import (
    "io"
    "log"
    "net/http"
)

func hello(w http.ResponseWriter, r *http.Request) {
    io.WriteString(w, "Hello world!")
    log.Println("hello.")
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/", hello)
    http.ListenAndServe(":8000", mux)
}

Problem is that whenever I load port 8000 in my web browser, this function is called twice. This is an issue because I intend to increment a counter on each page visit. With this behavior, counter gets incremented twice. OTOH, if I do curl localhost:8000, it is called only once.

I feel it's something really silly that I am missing here.

Answer 1

Waitting for answers