Haven't finished the book yet, but one thing I picked up from it already was the interesting way Erlang handles messages sent to processes, in how they're pattern-matched and saved for later if they're not what the process is looking for right at that moment.

At the heart of amqplib versions 0.3 or lower is a terrible mess that tries to deal with waiting for particular AMQP frames. Previously it would raise exceptions in some situations when it really shouldn't have. Specifically: if you had called basic_consume on a channel, and then called some other synchronous method like another basic_consume call - while it was expecting a basic_consume_ok response a basic_deliver could arrive and the library would raise an Exception because that wasn't expected.

A lame workaround is to use the nowait option most calls have, but I've now reworked things, cleaning up a lot of ugly code, and saving unexpected messages for later, similar to how Erlang does it. So now I believe the client library behaves in the way you'd generally expect. The improved code is currently in the Mercurial repository, and will be put out as a new release after it's had a chance to settle.