presto-iceberg/src/main/java/io/prestosql/plugin/iceberg/IcebergSplitSource.java/IcebergSplitSource/IcebergSplitSource
class IcebergSplitSource:    public IcebergSplitSource(
            CloseableIterable<CombinedScanTask> combinedScanIterable,
            TupleDomain<IcebergColumnHandle> predicate)
    {
        this.combinedScanIterable = requireNonNull(combinedScanIterable, "combinedScanIterable is null");
        this.predicate = requireNonNull(predicate, "predicate is null");

        this.fileScanIterator = Streams.stream(combinedScanIterable)
                .map(CombinedScanTask::files)
                .flatMap(Collection::stream)
                .iterator();
    }