code: func Init() {
  	HasInitalized = true
  
  	flag.Parse()
  
  	if taskOption.Mapper != "" || taskOption.Reducer != "" {
  		runner := &gleamRunner{Option: &taskOption}
  		runner.runMapperReducer()
  		os.Exit(0)
  	}
  }
docs: // Init determines whether the driver program will execute the mapper/reducer or not.
  // If the command line invokes the mapper or reducer, execute it and exit.
  // This function will invoke flag.Parse() first.