There is no guarantee that g_get_user_runtime_dir() is in a tmpfs. Using an explicit shared memory API seems safer for all POSIX platforms. Note that Android does not have shm_open() and only added memfd_create() since API level 30 (Android 11). Sponsored-by: Netflix Inc. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5328>