Progress bar moves down during download process

Progress bar moves down during download process

package main

import (
	"archive/zip"
	"bytes"
	"fmt"
	"github.com/debfig/bindview-cli/Tools"
	"github.com/schollz/progressbar/v3"
	"io"
	"net/http"
)

// DownloadUrl 下载地址
var DownloadUrl string = "https://github.com/bronze-ding/bindview-Template/archive/refs/heads/master.zip"

// DownloadFile 文件缓存区
var DownloadFile bytes.Buffer

func main() {

	// 获取命令行输入
	state, str := Tools.GetCmd()
	if state != 1 {
		return
	}

	req, _ := http.NewRequest("GET", DownloadUrl, nil)
	resp, _ := http.DefaultClient.Do(req)
	defer resp.Body.Close()

	bar := progressbar.DefaultBytes(
		resp.ContentLength,
		"正在下载模板压缩包 (.zip)",
	)

	io.Copy(io.MultiWriter(&DownloadFile, bar), resp.Body)

	ZipData, err := io.ReadAll(&DownloadFile)
	if err != nil {
		fmt.Println(err)
		return
	}

	ZipReader, _ := zip.NewReader(bytes.NewReader(ZipData), int64(len(ZipData)))

	// 解 .zip 压缩
	if err = Tools.Unzip("", ZipReader); err != nil {
		fmt.Println(err)
		return
	}

	// 文件重命名
	Tools.NewFileName(&str)

	// 输出命令提示
	Tools.CommandList(str)
}

Reproduce the report with the supplied Go example, starting at progressbar.DefaultBytes and the io.MultiWriter download path. Trace how progress updates are rendered during the download and use the screenshot and reported symptom to define done: the progress bar should remain in its intended position instead of moving down.