Sends a message to the current user's screen.
object $entity: An optional node entity, which will be added as $context['node'] if provided.
array $context: Array with the following elements:
function action_message_action(&$entity, $context = array()) {
if (empty($context['node'])) {
$context['node'] = $entity;
}
$context['message'] = token_replace(filter_xss_admin($context['message']), $context);
drupal_set_message($context['message']);
}