presto-main/src/main/java/io/prestosql/index/IndexManager.java/IndexManager/addIndexProvider
class IndexManager:    public void addIndexProvider(CatalogName catalogName, ConnectorIndexProvider indexProvider)
    {
        requireNonNull(catalogName, "catalogName is null");
        requireNonNull(indexProvider, "indexProvider is null");
        checkState(providers.putIfAbsent(catalogName, indexProvider) == null, "IndexProvider for connector '%s' is already registered", catalogName);
    }