func (t *Target) LastError() error {
	t.mtx.RLock()
	defer t.mtx.RUnlock()

	return t.lastError
}
func (t *Target) LastError() error {
	t.mtx.RLock()
	defer t.mtx.RUnlock()

	return t.lastError
}
// LastError returns the error encountered during the last scrape.