Go - Progress bar

package main

import (
    "fmt"
    "gopkg.in/cheggaaa/pb.v2"
    "time"
)

func main() {
    fmt.Println("test progress bar")
    file_size := int64(1024)
    now_size := int64(0)
    bar := pb.Start64(file_size)

    for {
        now_size += 50
        if now_size < file_size {
            bar.SetCurrent(now_size)
        } else {
            bar.SetCurrent(file_size)
            bar.Finish()
            break
        }
        time.Sleep(100 * time.Millisecond)
    }
}