Fetch has also lacked support for features that xhr has had for over a decade now. For example upload progress. It's slowly catching up though, upload progress is the only thing I'd choose xhr for.
That would show how quickly the data is passing into the native fetch call but doesn’t account for kind of internal buffer it might have, network latency etc
That is a way to approximate it, though I'd be curious to know the semantics compared to xhr - would they both show the same value at the same network lifecycle of a given byte?
