If used, 'opts.Marker` will cause many missed entries since results are returned
unsorted, and pools are serialized.
Switch to fully concurrent listing and merging across pools to return sorted entries.
Currently, the progress of the batch job is saved in inside the job
request object, which is normally not supported by MinIO. Though there
is no apparent bug, it is better to fix this now.
Batch progress is saved in .minio.sys/batch-jobs/reports/
Co-authored-by: Anis Eleuch <anis@min.io>
