public void Execute()
 {
     foreach (var track in m_pkg.Tracks)
     {
         Helmet hmd = m_helmets.FirstOrDefault(h => h.id == track.id);
         if (hmd == null)
         {
             hmd    = m_helmetsPool.Spawn().GetComponent <Helmet>();
             hmd.id = track.id;
             m_helmets.Add(hmd);
             m_addedHelmets.Push(hmd);
         }
         m_oldColors.Push(hmd.color);
         hmd.color = track.color;
         hmd.ReplaceAbs(track.position, track.rotation);
     }
 }