用xml.NewDecoder(xmlFile)解析Go/Golang中较大的XML文件时，如何实现进度计数器？

package main

import (
    "encoding/xml"
    "fmt"
    "io"
    "os"
)

type ProgressReader struct {
    r          io.Reader
    totalBytes int64
    readBytes  int64
}

func (pr *ProgressReader) Read(p []byte) (n int, err error) {
    n, err = pr.r.Read(p)
    pr.readBytes += int64(n)
    fmt.Printf("Progress: %d/%d bytes\n", pr.readBytes, pr.totalBytes)
    return
}

func main() {
    xmlFile, err := os.Open("large.xml")
    if err != nil {
        fmt.Println("Error opening XML file:", err)
        return
    }
    defer xmlFile.Close()

    fi, err := xmlFile.Stat()
    if err != nil {
        fmt.Println("Error getting file info:", err)
        return
    }
    fileSize := fi.Size()

    progressReader := &ProgressReader{
        r:          xmlFile,
        totalBytes: fileSize,
        readBytes:  0,
    }

    decoder := xml.NewDecoder(progressReader)

    // Start parsing the XML file
    for {
        _, err := decoder.Token()
        if err == io.EOF {
            break
        } else if err != nil {
            fmt.Println("Error parsing XML:", err)
            return
        }
    }

    fmt.Println("Parsing complete!")
}