This method returns TRUE on custom wrappers by default if you don't implement the stream_lock() method inside the wrapper : http://php.net/manual/en/streamwrapper.stream-lock.php
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
stream_supports_lock — Indique si le flux supporte les verrous
Indique si le flux supporte les verrous via la fonction flock().
stream
Le flux à tester.
This method returns TRUE on custom wrappers by default if you don't implement the stream_lock() method inside the wrapper : http://php.net/manual/en/streamwrapper.stream-lock.php