Clarify intended use of library

[kamalmarhubi]

Is it a ring buffer in the sense of constantly-being-written-to-buffer-of-recent-things sense, or is it a buffer in the buffer-between-a-producer-and-consumer sense? Examples would be handy!

[tokenrove]

I'll demo a usecase with rustls, but it applies everywhere you want to consume messages from a stream, where you might have read more than a message or less than a message, but want to be able to hand a buffer to the library producing messages without allocating, or moving things around in your buffer. Note that you can't do this with VecDeque because it doesn't wrap.