Concurrent HTTP GET Response generator

.go

// RespGen :: Concurrent HTTP GET Response generator
func RespGen(urls ...string) <-chan *http.Response {
	var wg sync.WaitGroup
	out := make(chan *http.Response)
	wg.Add(len(urls))
	for _, url := range urls {
		go func(url string) {
			req, err := http.NewRequest("GET", url, nil)
			if err != nil {
				panic(err)
			}
			req.Header.Set("user-agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:47.0) Gecko/20100101 Firefox/47.0")
			time.Sleep(3 * time.Second)
			resp, err := http.DefaultClient.Do(req)
			if err != nil {
				panic(err)
			}
			out <- resp
			wg.Done()
		}(url)
	}
	go func() {
		wg.Wait()
		close(out)
	}()
	return out
}