def send_request_to_service(service_name, message)
      if block_given?
        EventMachine.defer do
          yield send_request_to_service(service_name, message)
        end
      else
        send_HTTP_request(@channel.default_exchange, service_name, message)
      end
    end
def send_request_to_service(service_name, message)
      if block_given?
        EventMachine.defer do
          yield send_request_to_service(service_name, message)
        end
      else
        send_HTTP_request(@channel.default_exchange, service_name, message)
      end
    end
send a request to a service, this will wait for a response

 *service_name*:: the name of the service
 *message*:: the message to be sent

 This method can optionally take a block which will be executed asynchronously and yielded the response