def start
      queue = channel.queue("", :exclusive => true, :auto_delete => true)
      queue.bind(exchange_in, :routing_key => consumer.routing_key)
      queue.subscribe(&method(:handle_message))
      logger.info "Bind queue with routing key '#{consumer.routing_key}' to exchange '#{exchange_in.name}', waiting for messages..."
    end
def start
      queue = channel.queue("", :exclusive => true, :auto_delete => true)
      queue.bind(exchange_in, :routing_key => consumer.routing_key)
      queue.subscribe(&method(:handle_message))
      logger.info "Bind queue with routing key '#{consumer.routing_key}' to exchange '#{exchange_in.name}', waiting for messages..."
    end
Public: Initialize a ConsumerManager and adds itself as an observer to the consumer.

 consumer - An instance of Baton::Consumer
 channel - An AMQP channel
 exchange_in - An input exchange
 exchange_out - An output exchange
 Public: Creates a queue and binds it to the input exchange based on the consumer's
 routing key. Also adds handle_message as a callback method to queue.subscribe().

 Returns nothing.