How to get downloaded duration of Dash content?

Hi ExoPlayer team,

ExoPlayer version using: 2.15.1

We are following https://exoplayer.dev/downloading-media.html to download Mpeg-Dash content. We are using SimpleCache+CacheDataSource+DashDownloader to download the Dash content and hand over the CacheDataSource to ExoPlayer to do the playback.

We are able to download and playback of the item at the same time before the audio item is fully downloaded. And we can get the **"full duration"** of the item from ExoPlayer, and can get the **"bytesDownloaded"** from the DashDownloader callback. However, we don't find a way to get the **"downloaded duration"**

For example, say there is an audio file which is 10 minutes duration and the size is 100MB. When 60MB is downloaded and I try to play it, I would like to be able to get a **"download duration"** like 6 minutes into the audio.

Would like to know is there any API from the ExoPlayer library I can get this number?

Thanks,
Jianxing