minor symfony#20873 FrankenPHP can perform action after the response has been send (sungvadan)

This PR was submitted for the 7.2 branch but it was merged into the 6.4 branch instead.

Discussion
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FrankenPHP can perform action after the response has been send

Franken also implements fastcgi_finish_request PHP function. kernel.terminate event works well with franken.

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Commits
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fcfcacb Franken PHP can perform some action after the response has been streamed to the user

Author: javiereguiluz

components/http_kernel.rst

@@ -497,8 +497,8 @@ as possible to the client (e.g. sending emails).
 .. warning::
 
     Internally, the HttpKernel makes use of the :phpfunction:`fastcgi_finish_request`
-    PHP function. This means that at the moment, only the `PHP FPM`_ server
-    API is able to send a response to the client while the server's PHP process
+    PHP function. This means that at the moment, only the `PHP FPM`_ and `FrankenPHP`_ servers
+    API are able to send a response to the client while the server's PHP process
     still performs some tasks. With all other server APIs, listeners to ``kernel.terminate``
     are still executed, but the response is not sent to the client until they
     are all completed.
@@ -770,3 +770,4 @@ Learn more
 .. _FOSRestBundle: https://github.com/friendsofsymfony/FOSRestBundle
 .. _`PHP FPM`: https://www.php.net/manual/en/install.fpm.php
 .. _variadic: https://www.php.net/manual/en/functions.arguments.php#functions.variable-arg-list
+.. _`FrankenPHP`: https://frankenphp.dev