[LayaAir 2.0]Animator 怎么获取动画时长

   public function get normalizedTime():Number {
            return _normalizedTime;
        }
        
        /**
         * 获取当前动画的持续时间，以秒为单位。
         */
        public function get duration():Number {
            return _duration;
        }
 
 
animatorstate类里