Update for review per maurogeorge feedback

docs/general/instrumentation.md

@@ -1,7 +1,8 @@
 # Instrumentation
 
-ActiveModelSerializers uses the ActiveSupport::Notification API, which
-allows for subscribing to events, such as for logging.
+ActiveModelSerializers uses the
+[ActiveSupport::Notification API](http://guides.rubyonrails.org/active_support_instrumentation.html#subscribing-to-an-event),
+which allows for subscribing to events, such as for logging.
 
 ## Events
 
@@ -17,3 +18,20 @@ Payload (example):
   adapter: ActiveModel::Serializer::Adapter::Attributes
 }
 ```
+
+Subscribing:
+
+```ruby
+ActiveSupport::Notifications.subscribe 'render.active_model_serializers' do |name, started, finished, unique_id, data|
+  # whatever
+end
+ActiveSupport::Notifications.subscribe 'render.active_model_serializers' do |*args|
+  event = ActiveSupport::Notifications::Event.new(*args)
+  # event.payload
+  # whatever
+end
+
+## [LogSubscriber](http://api.rubyonrails.org/classes/ActiveSupport/LogSubscriber.html)
+
+ActiveModelSerializers includes an `ActiveModelSerializers::LogSubscriber` that attaches to
+`render.active_model_serializers`.