This is an optimization: there's no point in enqueuing unit and job
change notificiation signal messages into bus connection that aren't
fully set up yet.
This doesn't fix #8166 but should lower the load of messages enqueued
but not processed yet a bit.
/* Send to all direct buses, unconditionally */
SET_FOREACH(b, m->private_buses, i) {
+
+ /* Don't bother with enqueing these messages to clients that haven't started yet */
+ if (sd_bus_is_ready(b) <= 0)
+ continue;
+
r = send_message(b, userdata);
if (r < 0)
ret = r;