+ - sort out error codes for sd_bus_release_name(), distuingish: successful removal from foreign name, from non-existing name
+ - kdbus: matches against source or destination pids for an "strace -p"-like feel. Problem: The PID info needs to be available in userspace too...
+ - kdbus: we need a way to distuingish messages we got due to monitoring from normal messages, since we want to bind methods only to the latter
+ - kdbus: when we do "systemctl daemon-reexec" the call doesn't get properly cancelled
+ - figure out what to do when fields in the kdbus header and in the payload header do not match