You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: map_reduce.go
    path of file: ./repos/gleam/gio
    
    the code of the file until where you have to start completion: package gio

import (
	"flag"
	"fmt"
	"os"
	"reflect"
	"runtime"
	"sync"

	"github.com/chrislusf/gleam/pb"
)

type MapperId string
type ReducerId string
type Mapper func([]interface{}) error
type Reducer func(x, y interface{}) (interface{}, error)

type gleamTaskOption struc
    
func init() {
	flag.StringVar(&taskOption.Mapper, "gleam.mapper", "", "the generated mapper name")
	flag.StringVar(&taskOption.Reducer, "gleam.reducer", "", "the generated reducer name")
	flag.StringVar(&taskOption.KeyFields, "gleam.keyFields", "", "the 1-based key fields")
	flag.StringVar(&taskOption.ExecutorAddress, "gleam.executor", "", "executor address")
	flag.UintVar(&taskOption.HashCode, "flow.hashcode", 0, "flow hashcode")
	flag.IntVar(&taskOption.StepId, "flow.stepId", -1, "flow step id")
	flag.IntVar(&taskOption.TaskId, "flow.taskId", -1, "flow task id")
	flag.BoolVar(&taskOption.IsProfiling, "gleam.profiling", false, "profiling all steps")
}