文件监控 -- fsnotify

项目地址：
https://github.com/fsnotify/fsnotify

用法：

 package main
 import (
     "fmt"
     "github.com/fsnotify/fsnotify"
 )
 func main() {
     watcher, _ := fsnotify.NewWatcher()
     defer watcher.Close()
     done := make(chan bool)
     go func() {
         for {
             select {
             case event, ok := <- watcher.Events:
                 if !ok {
                     return
                 }
                 fmt.Println("事件：", event)
                 if event.Op & fsnotify.Write == fsnotify.Write {
                     fmt.Println("文件名：", event.Name)
                 }
             case err, ok := <-watcher.Errors:
                 if !ok {
                     return
                 }
                 fmt.Println("出错了：", err)
             }
         }
     }()
     err := watcher.Add("test.txt")
     if err != nil {
         fmt.Println("监控文件/文件夹失败：",err)
     }
     <- done
 }
 // 输出
 事件： "test.txt": WRITE
 文件名： test.txt