storage/remote/write.go
func (s *Storage) Appender() (storage.Appender, error) {
	return &timestampTracker{
		storage: s,
	}, nil
}
func (s *Storage) Appender() (storage.Appender, error) {
	return &timestampTracker{
		storage: s,
	}, nil
}
// Appender implements scrape.Appendable.