GitLab

* 111

* add history version test

* fix

* 111

* save

* ``

* fix1

* 111

* add save heterograph

* lint

* lint

* add tests

* minor fix

* fix

* docs

* add format tets

* use unique_ptr

* fix

* fix interface

* 111

* 111

* fix

* lint

* fix

* add support to s3

* fix

* fix

* fix leak

* fix

* fix docs

* fix

* linlt

* fix

* fix

* fix

* address comment

* address comment
Co-authored-by: Minjie Wang <wmjlyjemaine@gmail.com>
Co-authored-by: xiang song(charlie.song) <classicxsong@gmail.com>