rules/alerting.go
func (r *AlertingRule) ForEachActiveAlert(f func(*Alert)) {
	r.mtx.Lock()
	defer r.mtx.Unlock()

	for _, a := range r.active {
		f(a)
	}
}
func (r *AlertingRule) ForEachActiveAlert(f func(*Alert)) {
	r.mtx.Lock()
	defer r.mtx.Unlock()

	for _, a := range r.active {
		f(a)
	}
}
// ForEachActiveAlert runs the given function on each alert.
// This should be used when you want to use the actual alerts from the AlertingRule
// and not on its copy.
// If you want to run on a copy of alerts then don't use this, get the alerts from 'ActiveAlerts()'.