Go でマップを効率的に複製するにはどうすればよいですか?

package main

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

func main() {
    origMap := map[string]int{
        "key":  3,
        "clef": 5,
    }

    // Encode the original map into a buffer
    buf := &bytes.Buffer{}
    encoder := gob.NewEncoder(buf)
    err := encoder.Encode(origMap)
    if err != nil {
        log.Fatal(err)
    }

    // Decode the buffer into a new map
    var copyMap map[string]int
    decoder := gob.NewDecoder(buf)
    err = decoder.Decode(&copyMap)
    if err != nil {
        log.Fatal(err)
    }

    // Modify the copy without affecting the original
    copyMap["key"] = 2

    // Display both maps
    fmt.Println("Original:", origMap)
    fmt.Println("Copy:", copyMap)
}