code: func (m *Meta) GenAutoTableIDKeyValue(dbID, tableID, autoID int64) (key, value []byte) {
  	dbKey := m.dbKey(dbID)
  	autoTableIDKey := m.autoTableIDKey(tableID)
  	return m.txn.EncodeHashAutoIDKeyValue(dbKey, autoTableIDKey, autoID)
  }
docs: // GenAutoTableIDKeyValue generates meta key by dbID, tableID and corresponding value by autoID.