adding support to pickle and unpickle `AcceleratedOptimizer` (#811)
* adding support to pickle and unpickle `AcceleratedOptimizer`
* address comment
Co-Authored-By: Benjamin Bossan <BenjaminBossan@users.noreply.github.com>
* add test
* fixing test
* 😅
Co-authored-by: Benjamin Bossan <BenjaminBossan@users.noreply.github.com>