presto-main/src/main/java/io/prestosql/spiller/FileSingleStreamSpiller.java/FileSingleStreamSpiller/getAllSpilledPages
class FileSingleStreamSpiller:    @Override
    public ListenableFuture<List<Page>> getAllSpilledPages()
    {
        return executor.submit(() -> ImmutableList.copyOf(getSpilledPages()));
    }