text: '''
  Created on 2015年12月13日
  
  @author: sunshyran
  '''
  
  
  class AbstractMessageDriver(object):
      '''
      a message driver.
      '''
      def __init__(self):
          super().__init__()
          
          
      def startup(self, channel):
          '''
          \ start driver
          '''
          raise NotImplementedError
      
      
      def shutdown(self):
          '''
          \ stop driver
          '''
          raise NotImplementedError
          
          
      def invoke(self, message):
          '''
          \ send rpc message
          '''
          raise NotImplementedError
      
      
      def retrieve(self):
          '''
          \ recv rpc message
          '''
          raise NotImplementedError
  
  