GitLab

* fileio related interfaces should keep bc

* fix format

* update unit tests of transforms

* update format

* lazily infer client until calling get function of fileio

* [Refactor] Use new interface of fileio

* update ut

* remove file_client_args

* add * before backend_args

* refine backend_args description

* [Fix] fix some typo according to review

* fix comment

* [Feature] Add Part1 of data transform

* api.rst transform->transforms

* fix typo

* fix typo

* rename test_processing into test_transforms_processing for avoiding same name

* fix mypy

* fix comment

* fix comment