7bb68abb9f
This flag indicates that we're not interested in keeping half-open connections on a stream interface. It has the benefit of allowing the socket layer to cause an immediate write close when detecting an incoming read close. This releases resources much faster and saves one syscall (either a shutdown or setsockopt). This flag is only set by HTTP on the interface going to the server since we don't want to continue pushing data there when it has closed. Another benefit is that it responds with a FIN to a server's FIN instead of responding with an RST as it used to, which is much cleaner. Performance gains of 7.5% have been measured on HTTP connection rate on empty objects.