How to detect new or modified files

I found there are two ways to approach it, ReadDirectoryChangesW and FindFirstChangeNotification, I want to know what’s difference between them, performance or other???

From stackoverflow

• This is tagged for Winapi, but I give it a shot with .net anyway.

  You can use the FileSystemWatcher class from System.IO for this.

  static void Main(string[] args)
  {
      FileSystemWatcher fsw = new FileSystemWatcher("C:\\");
      fsw.Changed += new FileSystemEventHandler(fsw_Changed);
      fsw.Created += new FileSystemEventHandler(fsw_Created);
      fsw.Deleted += new FileSystemEventHandler(fsw_Deleted);
      fsw.EnableRaisingEvents = true;
      fsw.IncludeSubdirectories = true;
      fsw.Renamed += new RenamedEventHandler(fsw_Renamed);
  
      Console.Read();
  }
  
  static void fsw_Renamed(object sender, RenamedEventArgs e)
  {
      Console.WriteLine("{0} was changed to {1}", e.OldName, e.Name);
  }
  
  static void fsw_Deleted(object sender, FileSystemEventArgs e)
  {
      Console.WriteLine("{0} was deleted", e.Name);
  }
  
  static void fsw_Created(object sender, FileSystemEventArgs e)
  {
      Console.WriteLine("{0} was created", e.Name);
  }
  
  static void fsw_Changed(object sender, FileSystemEventArgs e)
  {
      Console.WriteLine("{0} was changed", e.Name);
  }