presto-main/src/main/java/io/prestosql/operator/TableScanWorkProcessorOperator.java/SplitToPages/close
class SplitToPages:        void close()
        {
            if (source != null) {
                try {
                    source.close();
                }
                catch (IOException e) {
                    throw new UncheckedIOException(e);
                }
            }
        }