Use FetchLoader for media segments download only to fix init segments caching issue in low latency mode
Created by: VasylS
Changes to address https://github.com/Dash-Industry-Forum/dash.js/issues/2837 Currently init segments caching in low latency mode is working incorrectly - it is storing only last data chunk in cache. Easiest way of fixing it is disabling fetch download for init segments.
- Extended 'Append Init fragment' log msgs with data size info
- Use FetchLoader for media segments download only.