Without this, a journal entry merely looks like this:
Stopping Multimedia Service ...
Which is obviously terrible from a branding perspective but also makes
it harder for users to figure out what process was responsible for this
entry.
/run/pipewire is initially created by pipewire.socket when it creates
the socket file, but it is owned by root with mode 0755.
In the .service unit, RuntimeDirectory=pipewire re-creates /run/pipewire
for user pipewire (owned by pipewire:pipewire, 0755) when this unit starts.
This is necessary for the pipewire daemon to be able to write the .lock file.
By default, when the service unit stops, systemd deletes this runtime
directory and therefore it also deletes the socket that is owned by
pipewire.socket. When this happens, the service is no longer
socket-activateable even though pipewire.socket is active.
RuntimeDirectoryPreserve=yes prevents the service unit from removing
this runtime directory and socket activation still works as expected
Add system service and socket in addition to the user service and
socket. The system service is started as pipewire user and group and
clients need to be in the pipewire group to be able to connect.
