presto-blackhole/src/main/java/io/prestosql/plugin/blackhole/BlackHoleMetadata.java/BlackHoleMetadata/getColumnHandles
class BlackHoleMetadata:    @Override
    public Map<String, ColumnHandle> getColumnHandles(ConnectorSession session, ConnectorTableHandle tableHandle)
    {
        BlackHoleTableHandle blackHoleTableHandle = (BlackHoleTableHandle) tableHandle;
        return blackHoleTableHandle.getColumnHandles().stream()
                .collect(toMap(BlackHoleColumnHandle::getName, column -> column));
    }