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: sendGetBack.go
    path of file: ./repos/nff-go/examples/nffPktgen/testing
    
    the code of the file until where you have to start completion: // Copyright 2018 Intel Corporation.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"flag"
	"fmt"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	"github.com/intel-go/nff-go/examples/nffPktgen/generator"
	"github.com/intel-go/nff-go/flow"
	"github.com/intel-go/nff-go/packet"
)

var (
	number, numberGot, recv uint64
	isCycled                bool
	testDoneEvent           *sync.Cond
)

type mapFlags struct {
	value map[interface{}]string
	set   bool
}

func parseStr(s string) string {
	indx := strings.Index(s, "'")
	substr := s[indx+1:]
	indx = strings.Index(substr, "'")
	return substr[:indx]
}

func parseIntOrStr(s string) interface{} {
	var parsed interface{}
	var err error
	parsed, err = strconv.Atoi(s)
	if err != nil {
		parsed = parseStr(s)
	}
	return parsed
}

func (m *mapFlags) String() string {
	s := ""
	for key, value := range (*m).value {
		if s != "" {
			s += ","
		}
		if k, ok := key.(int); ok {
			s += fmt.Sprintf("%d: '%s'", k, value)
		} else {
			s += fmt.Sprintf("'%v': '%s'", key, value)
		}
	}
	return s
}

func (m *mapFlags) Set(s string) error {
	ss := strings.Split(s, ",")
	(*m).value = make(map[interface{}]string)
	for _, val := range ss {
		val = strings.TrimSpace(val)
		pair := strings.Split(val, ":")
		value := parseStr(pair[1])
		(*m).value[parseIntOrStr(pair[0])] = value
	}
	(*m).set = true
	return nil
}

type listFlags struct {
	value []interface{}
	set   bool
}

func (l *listFlags) String() string {
	s := ""
	for _, value := range (*l).value {
		if s != "" {
			s += ", "
		}
		if v, ok := value.(int); ok {
			s += fmt.Sprintf("%d", v)
		} else {
			s += fmt.Sprintf("'%s'", value)
		}
	}
	return s
}

func (l *listFlags) Set(s string) error {
	ss := strings.Split(s, ",")
	for _, val := range ss {
		val = strings.TrimSpace(val)
		(*l).value = append((*l).value, parseIntOrStr
    
func main() {
	var (
		speed             uint64
		m                 sync.Mutex
		eachOutPortConfig mapFlags
		eachInPortConfig  listFlags
	)
	flag.Uint64Var(&number, "number", 0, "stop after generated number")
	flag.Uint64Var(&numberGot, "numberGot", 10000000, "stop after got number")
	flag.BoolVar(&isCycled, "cycle", false, "cycle execution")
	flag.Uint64Var(&speed, "speed", 6000000, "speed of fast generator, Pkts/s")
	flag.Var(&eachOutPortConfig, "outConfig", "specifies config per port portNum or file: 'path', 'pcapOut': 'path2'. For example: 1: 'ip4.json', 'mix.pcap': 'mix.json'")
	flag.Var(&eachInPortConfig, "inConfig", "specifies input ports and files 'path', portNum2, 'path2'. For example: 1, 'ip4.pcap', 0, 'mix.pcap'")
	flag.Parse()

	// Init NFF-GO system at 16 available cores
	config := flow.Config{
		CPUList:          "0-43",
		DisableScheduler: true,
	}
	flow.CheckFatal(flow.SystemInit(&config))

	testDoneEvent = sync.NewCond(&m)
	if !eachOutPortConfig.set {
		eachOutPortConfig.Set("0: '../testing/config.json'")
	}
	for key, value := range eachOutPortConfig.value {
		configuration, err := generator.ReadConfig(value)
		if err != nil {
			panic(fmt.Sprintf("%s config reading failed: %v", value, err))
		}
		context, err := generator.GetContext(configuration)
		flow.CheckFatal(err)
		outFlow, _, err := flow.SetFastGenerator(generator.Generate, speed, context)
		flow.CheckFatal(err)
		switch t := key.(type) {
		case int:
			flow.CheckFatal(flow.SetSender(outFlow, uint16(t)))
		case string:
			flow.CheckFatal(flow.SetSenderFile(outFlow, t))
		default:
			panic(fmt.Sprintf("Unrecognized type in outConfig: %v", key))
		}
	}
	for _, value := range eachInPortConfig.value {
		var (
			inFlow *flow.Flow
			err    error
		)
		switch t := value.(type) {
		case int:
			inFlow, err = flow.SetReceiver(uint16(t))
			flow.CheckFatal(err)
		case string:
			inFlow = flow.SetReceiverFile(t, -1)
		default:
			panic(fmt.Sprintf("Unrecognized type in inConfig: %v", value))
		}
		flow.CheckFatal(flow.SetHandler(inFlow, handleRecv, nil))
		flow.CheckFatal(flow.SetStopper(inFlow))
	}

	// Start pipeline
	go func() {
		flow.CheckFatal(flow.SystemStart())
	}()

	g := generator.GetGenerator()
	go func() {
		for {
			if g.GetGeneratedNumber() >= number {
				testDoneEvent.Signal()
			}
			println("Sent/Got", g.GetGeneratedNumber(), "/", atomic.LoadUint64(&recv), "packets")
			time.Sleep(time.Second)
		}
	}()

	// Wait for enough packets to arrive
	testDoneEvent.L.Lock()
	testDoneEvent.Wait()
	testDoneEvent.L.Unlock()
	println("Sent/Got", g.GetGeneratedNumber(), "/", atomic.LoadUint64(&recv), "packets")
}