The 0mq extension included with Akka has serious design problems, so I'm happy that mDialog has let us open source this. (I didn't write it, but I've worked on issues we've had using the original Akka extension). The Akka actor wrapping each 0mq socket sends itself a message to trigger a poll, which blocks for a configurable period of time. Messages easily queue up both in the actor's mailbox and on the 0mq socket. The default settings for the extension leave you with very high latency and poor throughput, but even if you modify the polling frequency and timeout you end up trading heavy CPU usage for what ends up being increased but still capped latency and throughput improvements.
This is awesome, wish it'd been there a week earlier!