Go の GET リクエストにクエリ文字列パラメータを効率的に追加するにはどうすればよいですか?

import (
    "fmt"
    "log"
    "net/http"
    "os"
    "net/url"
)

func main() {
    // Create a new request object with an initial URL.
    req, err := http.NewRequest("GET", "http://api.themoviedb.org/3/tv/popular", nil)
    if err != nil {
        log.Print(err)
        os.Exit(1)
    }

    // Get the existing query parameters from the request URL.
    q := req.URL.Query()

    // Add your querystring parameters to the `q` map.
    q.Add("api_key", "key_from_environment_or_flag")
    q.Add("another_thing", "foo & bar")

    // Encode the updated `q` map into a raw querystring and set it in the request.
    req.URL.RawQuery = q.Encode()

    // Retrieve the final URL with the querystring for debugging purposes.
    fmt.Println(req.URL.String())
    // Output:
    // http://api.themoviedb.org/3/tv/popular?another_thing=foo+%26+bar&api_key=key_from_environment_or_flag
}