func (rule *RecordingRule) LastError() error {
	rule.mtx.Lock()
	defer rule.mtx.Unlock()
	return rule.lastError
}
func (rule *RecordingRule) LastError() error {
	rule.mtx.Lock()
	defer rule.mtx.Unlock()
	return rule.lastError
}
// LastError returns the last error seen by the recording rule.