Issue: https://github.com/php/php-src/issues/7957
Comment Author: mvorisek
> ob_flush causes another call to callback with empty buffer: https://3v4l.org/aYQ92 Technically this is calling exit inside
> shutdown handler.> > > If you call exit() within one registered shutdown function, processing will stop
> > completely and no other registered shutdown functions will be called.> >
> > [register_shutdown_function](https://www.php.net/manual/en/function.register-shutdown-function.php)
you are correct, thanks!
https://3v4l.org/riNB9 - how can I clean the ob buffer inside
ob_start callback?
my desired output is:
```diff
-xunexpected output: x
+unexpected output: x
shutting down
```