Update event_listeners_subscribers.rst

Author: dmaicher

doctrine/event_listeners_subscribers.rst

@@ -186,57 +186,12 @@ interface and have an event method for each event it subscribes to::
 
 For a full reference, see chapter `The Event System`_ in the Doctrine documentation.
 
-Lazy loading for Event Listeners
+Performance considerations
 --------------------------------
 
-One subtle difference between listeners and subscribers is that Symfony can load
-entity listeners lazily. This means that your listener class will only be fetched
+One subtle difference between listeners and subscribers is that Symfony will load
+entity listeners lazily by default as of Symfony 4.2. This means that your listener class will only be fetched
 from the service container (and thus be instantiated) once the event it is linked
 to actually fires.
 
-Lazy loading might give you a slight performance improvement when your listener
-runs for events that rarely fire. Also, it can help you when you run into
-*circular dependency issues* that may occur when your listener service in turn
-depends on the DBAL connection.
-
-To mark a listener service as lazily loaded, just add the ``lazy`` attribute
-to the tag like so:
-
-.. configuration-block::
-
-    .. code-block:: yaml
-
-        services:
-            App\EventListener\SearchIndexer:
-                tags:
-                    - { name: doctrine.event_listener, event: postPersist, lazy: true }
-
-    .. code-block:: xml
-
-        <?xml version="1.0" ?>
-        <container xmlns="http://symfony.com/schema/dic/services"
-            xmlns:doctrine="http://symfony.com/schema/dic/doctrine">
-
-            <services>
-                <service id="App\EventListener\SearchIndexer" autowire="true">
-                    <tag name="doctrine.event_listener" event="postPersist" lazy="true" />
-                </service>
-            </services>
-        </container>
-
-    .. code-block:: php
-
-        use App\EventListener\SearchIndexer;
-
-        $container
-            ->autowire(SearchIndexer::class)
-            ->addTag('doctrine.event_listener', array('event' => 'postPersist', 'lazy' => 'true'))
-        ;
-
-.. note::
-
-    Marking an event listener as ``lazy`` has nothing to do with lazy service
-    definitions which are described :doc:`in their own section </service_container/lazy_services>`
-
-.. _`The Event System`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html
-.. _`the Doctrine Documentation`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html#entity-listeners
+So whenever possible it is preferable to use entity listeners instead of subscribers.