def observer_queue
      @observer_queue ||= client.create_queue([name, 'listener', Socket.gethostname, Process.pid].join('.'),
                                              models_exchange,
                                              queue_options:     {exclusive: true},
                                              subscribe_options: {manual_ack: true})
    end
def observer_queue
      @observer_queue ||= client.create_queue([name, 'listener', Socket.gethostname, Process.pid].join('.'),
                                              models_exchange,
                                              queue_options:     {exclusive: true},
                                              subscribe_options: {manual_ack: true})
    end
Create or return the observer queue which listens for ModelWatcher events