main.go

package main

import (
	"encoding/json"
	"fmt"

	msgpack "github.com/lestrrat/go-msgpack"
)

type User struct {
	ID string `json:"id" msgpack:"id"`
}

type UserWithName struct {
	User
	Name string `json:"name" msgpack:"name"`
}

func jsonMarshal(v interface{}) {
	fmt.Println("json")
	bytes, _ := json.Marshal(v)
	fmt.Println(string(bytes))
	var out interface{}
	json.Unmarshal(bytes, &out)
	fmt.Printf("%+v\n", out)
}

func msgpackMarshal(v interface{}) {
	fmt.Println("msgpack")
	bytes, _ := msgpack.Marshal(v)
	fmt.Println(string(bytes))
	var out interface{}
	msgpack.Unmarshal(bytes, &out)
	fmt.Printf("%+v\n", out)
}

func main() {
	u := UserWithName{}
	u.ID = "123"
	u.Name = "fuba"

	jsonMarshal(u)
	msgpackMarshal(u)
}

json
{"id":"123","name":"fuba"}
map[id:123 name:fuba]
msgpack
Userid123namefuba
map[User:map[id:123] name:fuba]