+ 'breakout' => array(), // List queue specifiers to break out when using Stomp queue.
+ // Default will share all queues for all sites within each group.
+ // Specify as <group>/<queue> or <group>/<queue>/<site>,
+ // using nickname identifier as site.
+ //
+ // 'main/distrib' separate "distrib" queue covering all sites
+ // 'xmpp/xmppout/mysite' separate "xmppout" queue covering just 'mysite'
+ 'max_retries' => 10, // drop messages after N failed attempts to process (Stomp)
+ 'dead_letter_dir' => false, // set to directory to save dropped messages into (Stomp)