Go HTTP POST 요청에서 쿠키를 효과적으로 관리하려면 어떻게 해야 합니까?

import (
    "net/http"
    "net/http/cookiejar"
)

jar, err := cookiejar.New(nil)
if err != nil {
    // Error handling
}

client := &http.Client{
    Jar: jar,
}

func Login(user, password string, client *http.Client) string {
    postUrl := "http://www.pge.com/eum/login"

    // Set up Login
    values := make(url.Values)
    values.Set("user", user)
    values.Set("password", password)

    // Submit form
    resp, err := client.PostForm(postUrl, values)
    if err != nil {
        log.Fatal(err)
    }
    defer resp.Body.Close()

    return "Hello"
}

func ViewBill(url string, client *http.Client) string {

    // Make the request using the client with cookies
    resp, err := client.Get(url)
    if err != nil {
        log.Fatal(err)
    }
    defer resp.Body.Close()

    return resp.Body
}