[streams] Byte streams (#300)

This is a tracking bug for progress on byte stream standardization.

Status:
- We've recently switched to adopt async read() (see #253).
- #176 is now obsolete.
- Requirements are summarized in the "Byte Streams" section in [Requirements.md](https://github.com/whatwg/streams/blob/master/Requirements.md).

Sub issues:
- [ ] Naming the reader getter methods #294

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/streams/issues/300