Update example and docs

[cake-duke]

This example failed. Looking at the code there's never any "excess", as the channel type is socketready = Channel{Tuple{IO, Response}}(0).

At first I thought this was just an outdated example, what confuses me is that from git blame I can't tell why someone thought there was an excess. Maybe it's just a mistake, as opposed to being out of date, or maybe I'm missing something.

Please review.