You can use one protocol for the broadcaster to stream to the provider (Twitch). You can use the same protocol, or a different one, to deliver video to viewers.

You can use one protocol for the broadcaster to stream to the provider (Twitch). You can use the same protocol, or a different one, to deliver video to viewers. If you use HLS to deliver video to viewers, you can cache segments in a CDN. Your CDN. Someone else's CDN. You'll add some latency, but your bill will be lower.