    # File lib/amqp/deprecated/rpc.rb, line 115
          def method_missing(selector, *args, &block)
            @channel.once_open do
              message_id   = "message_identifier_#{rand(1_000_000)}"

              if block
                @handlers[message_id] = block
                @exchange.publish(Marshal.dump([selector, *args]), :routing_key => @server_queue_name, :reply_to => @queue.name, :message_id => message_id)
              else
                @exchange.publish(Marshal.dump([selector, *args]), :routing_key => @server_queue_name, :message_id => message_id)
              end
            end
          end