Byte stream support for `stream()`?

[saschanaz]

This succeeds on Firefox but fails on Chrome:

new Blob([1,2]).stream().getReader({mode: 'byob'})

But the spec does not actually sets up the stream as a byte stream. It makes sense for file related APIs to support byte stream reader, should the spec change?

See also whatwg/fetch#267 for Fetch.