presto-hive/src/main/java/io/prestosql/plugin/hive/HiveSplitSource.java/PerBucket/borrowBatchAsync
class PerBucket:        <O> ListenableFuture<O> borrowBatchAsync(OptionalInt bucketNumber, int maxSize, Function<List<InternalHiveSplit>, BorrowResult<InternalHiveSplit, O>> function);