Timeout requests with a context

	// httpbin.org is a service for testing HTTP client
	// this URL waits 3 seconds before returning a response
	uri := "https://httpbin.org/delay/3"
	req, err := http.NewRequest("GET", uri, nil)
	if err != nil {
		log.Fatalf("http.NewRequest() failed with '%s'\n", err)
	}

	// create a context indicating 100 ms timeout
	ctx, _ := context.WithTimeout(context.Background(), time.Millisecond*100)
	// get a new request based on original request but with the context
	req = req.WithContext(ctx)

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		// the request should timeout because we want to wait max 100 ms
		// but the server doesn't return response for 3 seconds
		log.Fatalf("http.DefaultClient.Do() failed with:\n'%s'\n", err)
	}
	defer resp.Body.Close()