presto-hive/src/main/java/io/prestosql/plugin/hive/parquet/HdfsParquetDataSource.java/HdfsParquetDataSource/readLargeDiskRanges
class HdfsParquetDataSource:    private <K> Map<K, ChunkReader> readLargeDiskRanges(Map<K, DiskRange> diskRanges)
    {
        if (diskRanges.isEmpty()) {
            return ImmutableMap.of();
        }

        ImmutableMap.Builder<K, ChunkReader> slices = ImmutableMap.builder();
        for (Map.Entry<K, DiskRange> entry : diskRanges.entrySet()) {
            slices.put(entry.getKey(), new ReferenceCountedReader(entry.getValue()));
        }
        return slices.build();
    }