public hourglass add_hourglass(float total_time, callback cb)
    {
        hourglass hg = new hourglass(total_time, cb);

        hourglasses.Add(hg.guid, hg);
        return(hg);
    }
    private void Awake()
    {
        _audioSource = GetComponent <AudioSource>();
        _hourglass   = GetComponent <hourglass>();

        instance = this;
    }
 public void cancle_hourglass(hourglass hg)
 {
     if (hourglasses.ContainsKey(hg.guid))
     {
         hourglasses [hg.guid].pause();
         hourglasses.Remove(hg.guid);
     }
 }