Features:
+* kdbus: for some reason "busctl monitor" only shows metadata for signal msgs, never method call or method reply msgs
+
* add "systemctl start -v foobar.service" that shows logs of a service
while the start command runs. This is non-trivial to do without
races though, since we should flush out all journal messages before
ReadOnlyDirectories=... for whitelisting files for a service.
* sd-bus:
- - kdbus: maybe add euid, egid, fsuid, fsgid, controlling tty and ppid metadata fields
+ - kdbus: maybe add controlling tty and ppid metadata fields
- see if we can introduce a new sd_bus_get_owner_machine_id() call to retrieve the machine ID of the machine of the bus itself
- when kdbus does not take our message without memfds, try again with memfds
- systemd-bus-proxyd needs to enforce good old XML policy