# File lib/bunny/queue08.rb, line 86
    def ack(opts={})
      # Set delivery tag
      if delivery_tag.nil? and opts[:delivery_tag].nil?
        raise Bunny::AcknowledgementError, "No delivery tag received"
      else
        self.delivery_tag = opts[:delivery_tag] if delivery_tag.nil?
      end

      opts = {:delivery_tag => delivery_tag, :multiple => false}.merge(opts)

      client.send_frame(Qrack::Protocol::Basic::Ack.new(opts))

      # reset delivery tag
      self.delivery_tag = nil
    end