Go のマップ内に値のリストを効率的に保存するにはどうすればよいですか?

package main

import (
    "fmt"
    "container/list"
)

func main() {
    // Create a map of string to list
    x := make(map[string]*list.List)

    // Assign a new list to a key in the map
    x["key"] = list.New()

    // Push a value to the list
    x["key"].PushBack("value")

    // Retrieve the first value from the list associated with the key
    fmt.Println(x["key"].Front().Value)
}

package main

import "fmt"

func main() {
    // Create a map of string to string slices
    x := make(map[string][]string)

    // Append values to the slice associated with the key
    x["key"] = append(x["key"], "value")
    x["key"] = append(x["key"], "value1")

    // Retrieve the first and second values from the slice
    fmt.Println(x["key"][0])
    fmt.Println(x["key"][1])
}