[pubsubhubbub] 0.2 core review; "as bytes" in subscription request

[Tim Bray]

6.1 Subscriber Sends Subscription Request
hub.secret ... "(as bytes)".  Really, as bytes? I assume there could
be a charset= parameter on the media-type and this could be in a
variety of encodings. Presumably the hub.secret is actually going to
be expressed as characters in whatever charset is operative.
Arbitrary bytes are a problem unless you have a system for escaping
the \r\n they use to separate lines in this kind of body.  Or am I
missing something?