GitLab

* support interleaved pipeline

* fix unit test

* remove virtual stage test in stage mgr

* add droped type hint and updated bwd

* add unit test for 1f1b

* polish code

* polish code and update ut version

* fix

* [api] update optimizer wrapper to fit pipeline

* [pipeline] add base schedule

* [pipeline] add 1f1b schedule

* [test] add pipeline schedule utils test

* [pipeline] fix import