golang handling panic

gistfile1.go

package main

import (
	"log"
	"net/http"
	"sync"
)

type Handler struct{}

func (handler Handler) ServeHTTP(
	response http.ResponseWriter, request *http.Request,
) {
	defer func() {
		if err := recover(); err != nil {
			log.Printf("do not panic, please")
		}
	}()

	workers := &sync.WaitGroup{}
	// there is 1, not 2
	workers.Add(1)

	go func() {
		workers.Done()
	}()

	go func() {
		workers.Done()
		//there is will be error 'negative WaitGroup counter'
	}()

	workers.Wait()
}

func main() {
	handler := Handler{}
	http.ListenAndServe(":9090", handler)
}