presto-main/src/main/java/io/prestosql/operator/PartitionedLookupSource.java/PartitionedLookupSource/close
class PartitionedLookupSource:    @Override
    public void close()
    {
        if (closed) {
            return;
        }

        try (Closer closer = Closer.create()) {
            if (outerPositionTracker != null) {
                closer.register(outerPositionTracker::commit);
            }
            Arrays.stream(lookupSources).forEach(closer::register);
        }
        catch (IOException e) {
            throw new UncheckedIOException(e);
        }

        closed = true;
    }