Re: [streams] Add ReadableByteStream definition (#343)

In terms of the MVP for helping MSE, I think we want:

- Complete class definitions
- AcquireReadableByteStreamReader(rbs) and ReadFromReadableByteStreamReader(reader, destView)
- The text sections filled in ("Readable Byte Streams" and "Using Readable Byte Streams").

I think it'd also be ideal to not have any known-inaccurate algorithms, and for the ones we're unsure on have a warning `<div>`.

---
Reply to this email directly or view it on GitHub:
https://github.com/whatwg/streams/pull/343#issuecomment-95249601