public Playing(FadePlayer player)
     : base(player)
 {
     if (player.audioSource.get_isPlaying())
     {
         return;
     }
     player.audioSource.Play();
 }
 public Wait(FadePlayer player)
     : base(player)
 {
 }
 public State(FadePlayer player)
 {
     this.player = player;
 }
 public FadeOut(FadePlayer player)
     : base(player)
 {
     player.currentVolume = player.audioSource.get_volume();
 }
 public Paused(FadePlayer player)
     : base(player)
 {
     this.preState = player.nowState;
     player.audioSource.Pause();
 }
 public FadeIn(FadePlayer player)
     : base(player)
 {
     player.audioSource.Play();
     player.audioSource.set_volume(0.0f);
 }