Sort String in Golang

package main

import (
    "fmt"
    "sort"
)

func main() {
    str := "bfcawd"
    s := []rune(str)
    sort.Slice(s, func(i int, j int) bool { return s[i] < s[j] })
    fmt.Println(string(s))
}    

Output

abcdfw