如何使用 gob 解码接口

package main

import (
    "encoding/gob"
    "fmt"
    "log"
    "os"
)

type User struct {
    Username string
    Password string
}

type Admin struct {
    Username string
    Password string
    IsAdmin  bool
}

type Deleter interface {
    Delete()
}

func (u User) Delete() {
    fmt.Println("User ==> Delete()")
}

func (a Admin) Delete() {
    fmt.Println("Admin ==> Delete()")
}

func main() {

    file, _ := os.Open("user.gob")

    adminFile, _ := os.Open("admin.gob")

    defer file.Close()

    defer adminFile.Close()

    gob.Register(User{}) // registering the type allows us to encode it

    gob.Register(Admin{}) // registering the type allows us to encode it

    var admin Deleter

    var user Deleter

    userDecoder := gob.NewDecoder(file)

    adminDecoder := gob.NewDecoder(adminFile)

    user = InterfaceDecode(userDecoder)

    admin = InterfaceDecode(adminDecoder)

    fmt.Println(user)

    fmt.Println(admin)

}

func InterfaceDecode(decoder *gob.Decoder) Deleter {

    var d Deleter

    if err := decoder.Decode(&d); err != nil {
        log.Fatal(err)
    }

    return d

}