add a hook at point of enqueuing notices

EVENTS.txt

@@ -254,3 +254,10 @@ StartApiRss: after the rss <channel> element is started
 StartApiAtom: after the <feed> element is started
 - $action: action object being shown
 
+StartEnqueueNotice: about to add a notice to the queues (good place to add a new transport)
+- $notice: the notice being added
+- &$transports: modifiable list of transports (as strings) to queue for
+
+EndEnqueueNotice: after adding a notice to the queues
+- $notice: the notice being added
+- $transports: modifiable list of transports to use

lib/util.php

@@ -915,11 +915,16 @@ function common_enqueue_notice($notice)
         }
     }
 
-    $qm = QueueManager::get();
+    if (Event::handle('StartEnqueueNotice', array($notice, &$transports))) {
 
-    foreach ($transports as $transport)
-    {
-        $qm->enqueue($notice, $transport);
+        $qm = QueueManager::get();
+
+        foreach ($transports as $transport)
+        {
+            $qm->enqueue($notice, $transport);
+        }
+
+        Event::handle('EndEnqueueNotice', array($notice, $transports));
     }
 
     return true;