func Adapter(db *tsdb.DB, startTimeMargin int64) storage.Storage {
	return &adapter{db: db, startTimeMargin: startTimeMargin}
}
func Adapter(db *tsdb.DB, startTimeMargin int64) storage.Storage {
	return &adapter{db: db, startTimeMargin: startTimeMargin}
}
// Adapter return an adapter as storage.Storage.