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: main.go
    path of file: ./repos/training/example25-traefik-golang-app-lets-encrypt
    
    the code of the file until where you have to start completion: package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"time"
)

// HelloWorld for hello world
func HelloWorld() string {
	return "Hello World, traefik workshop!"
    
func pinger(port string) error {
	resp, err := http.Get("http://localhost:" + port)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != 200 {
		return fmt.Errorf("server returned not-200 status code")
	}

	return nil
}