user@debian:/tmp/systembus-notify$ ./systembus-notify &
[2] 8710
user@debian:/tmp/systembus-notify$ dbus-send --system / net.nuetzlich.SystemNotifications.Notify 'string:summary text only'
user@debian:/tmp/systembus-notify$ summary text only
(null)
dbus-send --system / net.nuetzlich.SystemNotifications.Notify 'string:summary text' 'string:and body text'summary text only
(null)