How to delete cookie

I wrote a web application that set a cookie and delete it. To clarify to scenario what I mean look at the following code snippet.

package main
import (
"fmt"
"github.com/gorilla/mux"
"net/http"
"time"
)
func rootHandler(rw http.ResponseWriter, r *http.Request) {
fmt.Fprintf(rw, "Hello Foo")
}
func setCookieHandler(rw http.ResponseWriter, r *http.Request) {
c := &http.Cookie{
Name:     "storage",
Value:    "value",
Path:     "/",
MaxAge:   0,
HttpOnly: true,
}
http.SetCookie(rw, c)
}
func deleteCookieHandler(rw http.ResponseWriter, r *http.Request) {
c, err := r.Cookie("storage")
if err != nil {
panic(err.Error())
}
c.Name = "Deleted"
c.Value = "Unuse"
c.Expires = time.Unix(1414414788, 1414414788000)
}
func readCookieHandler(rw http.ResponseWriter, r *http.Request) {
c, err := r.Cookie("storage")
if err != nil {
panic(err.Error())
}
fmt.Println(c.Expires)
}
func evaluateCookieHandler(rw http.ResponseWriter, r *http.Request) {
c, err := r.Cookie("storage")
if err != nil {
panic(err.Error())
}
if time.Now().After(c.Expires) {
fmt.Println("Cookie is expired.")
}
}
func main() {
mux := mux.NewRouter()
mux.HandleFunc("/", rootHandler)
mux.HandleFunc("/cookie", setCookieHandler)
mux.HandleFunc("/delete", deleteCookieHandler)
mux.HandleFunc("/read", readCookieHandler)
mux.HandleFunc("/eval", evaluateCookieHandler)
http.ListenAndServe(":3000", mux)
}

As you can see, when I visit /cookie location, it will be set a cookie as expected. Then when I call /delete, it should change the name, value and expired time from cookie. The expired time is changed, but name and value not.

What do I want is, to delete the cookie from browser for sign out in a authentication system, when user click sign out button to delete cookie.
I also discover this link and follow the advice, but does not work as expected.

To delete a cookie named "storage", sending set-cookie with the same cookie name.

deleteCookieHandler() should be as follows

c := &http.Cookie{
Name:     "storage",
Value:    "",
Path:     "/",
Expires: time.Unix(0, 0),
HttpOnly: true,
}
http.SetCookie(rw, c)

MaxAge=0 means no 'Max-Age' attribute specified.

MaxAge<0 means delete cookie now, equivalently 'Max-Age: 0'

MaxAge>0 means Max-Age attribute present and given in seconds

c := &http.Cookie{
Name:     "storage",
Value:    "",
Path:     "/",
MaxAge:   -1,
HttpOnly: true,
}
http.SetCookie(rw, c)

Cookies are keyed by name, so when you "change" the name, you actually "create" a different cookie, already expired.

Keep the name the same and it should work, but don't forget to take some time one day to read about cookies and how they work.