How to download HLS videos for offline viewing in Windows 10

[zydjohnHotmail]

Hello:
I found this repo, it seems to be a good one.
Now I have this requirement: I want to download a few live streaming videos (.mp4 format) from some (5 to 10) m3u8 URLs. Some of them (2 to 3) are running at the same time, but they may last different times (from 2 hours to 3 hours), like the Olympics games.
I want to know how I can write some C# code to download all those m3u8 URLs and save them to local hard drive and view them later off-line?
Thanks,
PS: the m3u8 URL has the format like:
https://video.maker.by:999/o1/stream99/chunks.m3u8?sessionid=XXXXXX
I am using Windows 10 Version 21H1, and Visual Studio 2019 Version 16.10.4