With add_action, I want to intercept as early as I can in my plugin and send a 304 Not Modified header per some rules. Does anyone know what the order is of events? When I view this page, it seems to hint that the best place for this would be plugins_loaded, and that it comes before the init event. Is that correct? The page in that link doesn't describe what the event order is, but seems to imply it.
If you are wanting to send a header either
init will work. But it is recommended to use the
send_headers action that is fired just after the request is parsed, also if your rules depend on data in
WP_Query you will need to use