package mainimport (    "strings"    "net/http"    "encoding/json"    "fmt")func main() {    j := `{"url":"http://localhost/test/take-request", "params":{"name":"John","age":"20"},"type":"get"}`    // k := `{"url":"http://localhost/test/take-request", "params":{"gender":"m","a":"20"},"type":"post"}`    request := map[string]interface{}{}    err := json.Unmarshal([]byte(j), &request)    if err != nil {        panic(err)    }    fmt.Println(request)    requestType = strings.ToUpper(request["type"]);    requestUrl = request["url"];    fmt.Println(request["params"])    // how do i get the keys and their values from params.    // note params is dynamic.    for _, v := range request["params"].(map[string]interface{}) {        // println(v)        switch t := v.(type) {        case string, []int:            fmt.Println(t)        default:            fmt.Println("wrong type")        }    }    sendRequest(requestType, requestUrl)}func sendRequest(type string, url string) string {    req, err := http.NewRequest(type, url, nil)    client := &http.Client{}    resp, err := client.Do(req)    if err != nil {        panic(err)    }    defer resp.Body.Close()    body, _ := ioutil.ReadAll(resp.Body)    fmt.Println("response Body:", string(body))    return string(body)}我如何遍歷參數(shù)是interface我如何獲得密鑰及其值