First pass at some documentation for AsyncBufferSequence (#90)
First pass at some documentation for AsyncBufferSequence (#90)

* First pass at some documentation for AsyncBufferSequence

* Apply suggestions from code review

Co-authored-by: Chris Adamson <c8a3874119f29e9065ce7a15c8810bd95ffb4889@gmail.com>

Co-authored-by: Chris Adamson <c8a3874119f29e9065ce7a15c8810bd95ffb4889@gmail.com>
apple/swift-async-algorithms,apple/swift-async-algorithms,apple/swift-async-algorithms