+ - synthesized messages should get serial number (uint32_t) -1
+ - when triggering property change events, allow a NULL strv indicate that all properties listed as such are send out as changed
+ - enforce signatures on response messages
+ - see if we can drop more message validation on the sending side
+ - support "const" properties as flag
+ - add API to clone sd_bus_message objects
+ - SD_BUS_COMMENT() macro for inclusion in vtables, syntax inspired by gdbus
+ - unelss configure option is specified refuse connecting and creating kdbus, so that we can break compat
+
+* sd-event
+ - allow multiple signal handlers per signal
+ - when a handler returns an error, just turn off its event source,
+ but do not return anything up to the event loop caller. Instead
+ add parameter to sd_event_request_quit() to take retval. This way
+ errors rippling upwards are the option, not the default
+ - child pid handling: first invoke waitid(WNOHANG) and call event handler, only afterwards reap the process
+ - native support for watchdog stuff