shutdown action-hook . WP 1.2.0

Fires just before PHP shuts down execution.

Usage

add_action( 'shutdown', 'action_function_name_300' );
function action_function_name_300(){
	// action...
}

Where the hook is called

do_action( 'shutdown' );

Where the hook is used (in WP core)

add_action( 'shutdown', 'wp_ob_end_flush_all', 1 );