代码实例：

package main

import (
    "encoding/base64"
    "io/ioutil"
    "strings"
)

var (
    // base 64 数据
    data = `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`
)

func main() {
    reader := strings.NewReader(data)
    decoder := base64.NewDecoder(base64.StdEncoding, reader)
    // 以流式解码
    buf := make([]byte, 2)
    // 保存解码后的数据
    dst := ``
    for {
        n, err := decoder.Read(buf)
        if n == 0 || err != nil {
            break
        }
        dst += string(buf[:n])
    }
    ioutil.WriteFile(`解码完成的音乐文件.mp3`, []byte(dst), 0666)
}