GitLab

* update distributed training doc.

* explain data split.

* fix message passing.

* id mapping.

* fix.

* test data reshuffling.

* fix a bug.

* fix test.

* Revert "fix test."

This reverts commit 907f1dd88994894db94ffcd77b5995279f76b489.

* Revert "fix a bug."

This reverts commit ff0a4d893bbe4911a75ecb04bcbd9bc65315166b.

* Revert "test data reshuffling."

This reverts commit 99bb2f6405de67fc73652220b02e7184461c3e5e.
Co-authored-by: Zheng <dzzhen@3c22fba32af5.ant.amazon.com>