minor #11663 [HttpClient] Documented the cancel() method (javiereguiluz)

This PR was merged into the 4.4 branch.

Discussion
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[HttpClient] Documented the cancel() method

Fixes #11658.

Commits
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a983ece [HttpClient] Documented the cancel() method

Author: OskarStark

components/http_client.rst

@@ -380,6 +380,23 @@ the "foreach" in the snippet with this one, the code becomes fully async::
     Use the ``user_data`` option combined with ``$response->getInfo('user_data')``
     to track the identity of the responses in your foreach loops.
 
+Canceling Responses
+~~~~~~~~~~~~~~~~~~~
+
+Responses can be canceled at any moment before they are completed using the
+``cancel()`` method::
+
+    foreach ($client->stream($responses) as $response => $chunk) {
+        // ...
+
+        // if some condition happens, cancel the response
+        $response->cancel();
+    }
+
+.. versionadded:: 4.4
+
+    The ``cancel()`` method was introduced in Symfony 4.4.
+
 Dealing with Network Timeouts
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~