How can I tell if net/http's ResponseWriter.Write() has been called?

Question

Suppose I have a chain of net/http Handlers, and an early one responds with an HTTP error (http.StatusInternalServerError, for instance). How can I detect this in

Answer 1

First: a lighter-weight solution may exist.

However, if you cannot find one, consider using x/net/context to allow you to implement timeouts, deadlines, and of course, early termination of middleware chains.