RUM SDK: add more details on view lifecycle and beforeSend (#29377)

* RUM SDK: add more details on view lifecycle and beforeSend

* 👌️ remove empty lines

Co-authored-by: Janine Chan <[email protected]>

* 👌️ improve phrasing

Co-authored-by: Janine Chan <[email protected]>

---------

Co-authored-by: Janine Chan <[email protected]>

Author: bcaudan

content/en/real_user_monitoring/browser/advanced_configuration.md

@@ -552,6 +552,17 @@ You can update the following event properties:
 
 The RUM Browser SDK ignores modifications made to event properties not listed above. For more information about event properties, see the [RUM Browser SDK GitHub repository][15].
 
+**Note**: Unlike other events, view events are sent multiple times to Datadog to reflect the updates occurring during their lifecycle. An update on a previous view event can still be sent while a new view is active. Datadog recommends being mindful of this behavior when modifying the content of a view event.
+
+```javascript
+beforeSend: (event) => {
+    // discouraged, as the current view name could be applied to both the active view and the previous views
+    event.view.name = getCurrentViewName()
+
+    // recommended
+    event.view.name = getViewNameForUrl(event.view.url)
+}
+```
 ### Discard a RUM event
 
 With the `beforeSend` API, discard a RUM event by returning `false`: