incus listener add handler

foo.go

// ...
listener, err := conn.GetEventsAllProjects()
_, err = listener.AddHandler(
[]string{
	api.EventLifecycleInstanceCreated,
	api.EventLifecycleInstanceReady,
	api.EventLifecycleInstanceRestarted,
}, func(event api.Event) {
	ctx.Logger().Debug("handling instance create event", zap.Any("event", event))

	err := u.provisionCandidates(ctx, conn)
	if err != nil {
		ctx.Logger().Error("unable to provision candidates", zap.Error(err))
	}
})
 // ...