ex10

Exercise 8.10 (P253)

HTTP requests may be cancelled by closing the optional Cancel channel in the http.Request struct. Modify the web crawler of Selection 8.6 to support cancellation.

Hint: the http.Get convenience function does not give you an opportunity to customize a Request. Instead, create the request using http.NewRequest, set its Cancel field, then perform the request by calling http.DefaultClient.Do(req).