For fairness's sake, I'd like to point out that Nodejs has the same behaviour. Helping a new developer create a web server, we fell into the bugs the author is

For fairness's sake, I'd like to point out that Nodejs has the same behaviour. Helping a new developer create a web server, we fell into the bugs the author is talking about a few times. I was always quick to spot the problem with the benefit of experience, but a newbie debugging a "response was already sent" error was not the simplest thing in the world.