feature symfony#3539 [Stopwatch] Describe retrieval of StopwatchEvent (jochenvdv)

This PR was merged into the master branch.

Discussion
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[Stopwatch] Describe retrieval of StopwatchEvent

See [symfony/symfony#10198](symfony/symfony#10198)

| Q | A |
|----------------|------|
| Doc fix | no |
| New docs | yes |
| Applies to | master |
| Fixed tickets | - |

Commits
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0ee15d3 Fix versionadded
295f109 Add reason for getEvent()
ac484f4 Made suggested tweaks
2ca9bd5 Describe retrieval of StopwatchEvent

Author: weaverryan

components/stopwatch.rst

@@ -31,6 +31,16 @@ microtime by yourself. Instead, use the simple
     // ... some code goes here
     $event = $stopwatch->stop('eventName');
 
+.. versionadded:: 2.5
+    The ``getEvent()`` method was introduced in Symfony 2.5
+
+The :class:`Symfony\\Component\\Stopwatch\StopwatchEvent` object can be retrieved from the 
+:method:`Symfony\\Component\\Stopwatch\\Stopwatch::start`, 
+:method:`Symfony\\Component\\Stopwatch\\Stopwatch::stop`, 
+:method:`Symfony\\Component\\Stopwatch\\Stopwatch::lap` and 
+:method:`Symfony\\Component\\Stopwatch\\Stopwatch::getEvent` methods. 
+The latter should be used when you need to retrieve the duration of an event while it is still running.
+
 You can also provide a category name to an event::
 
     $stopwatch->start('eventName', 'categoryName');