[Refactor] data flow (#1956)

* [WIP] Refactor data flow

* model return

* [WIP] Refactor data flow

* support data_samples is optional

* fix benchmark

* fix base

* minors

* rebase

* fix api

* ut

* fix api inference

* comments

* docstring

* docstring

* docstring

* fix bug of slide inference

* add assert c > 1