flutter - 在后台播放音频时如何获取 currentDuration？

Question

我正在使用assets_audio_player包，如何在应用程序被杀死之前在后台播放音频时获取播放器 currentDuration？当小部件可见时，此代码可以完美运行

assetsAudioPlayer.builderRealtimePlayingInfos(builder: (context,RealtimePlayingInfos? playerInfo) {
              if (playerInfo == null) {
                return const SizedBox();
              }
              else
              { duration = playerInfo.duration;
                curPosition = playerInfo.currentPosition.inSeconds;
               }