feature #12213 [Process] Document the getLastOutputTime() method. (OskarStark)

This PR was merged into the 4.4 branch.

Discussion
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[Process] Document the getLastOutputTime() method.

fixes #12194

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Commits
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e6d63ea [Process] Document the getLastOutputTime() method.

Author: OskarStark

components/process.rst

@@ -96,6 +96,12 @@ with a non-zero code)::
         echo $exception->getMessage();
     }
 
+.. tip::
+
+    You can get the last output time in seconds by using the
+    :method:`Symfony\\Component\\Process\\Process::getLastOutputTime` method.
+    This method returns ``null`` if the process wasn't started!
+
 Using Features From the OS Shell
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