code: func NewStateStore(gc *TombstoneGC) (*Store, error) {
  	// Create the in-memory DB.
  	schema := stateStoreSchema()
  	db, err := memdb.NewMemDB(schema)
  	if err != nil {
  		return nil, fmt.Errorf("Failed setting up state store: %s", err)
  	}
  
  	// Create and return the state store.
  	s := &Store{
  		schema:       schema,
  		db:           db,
  		abandonCh:    make(chan struct{}),
  		kvsGraveyard: NewGraveyard(gc),
  		lockDelay:    NewDelay(),
  	}
  	return s, nil
  }
docs: // NewStateStore creates a new in-memory state storage layer.