accelerate

4170f395 - Get rid of calling get_scale() by patching the step method of optimizer. (#1720)

Get rid of calling get_scale() by patching the step method of optimizer. (#1720) * Get rid of calling get_scale() by patching the step method of optimizer. * Fix when step() is already patched by other parties. * support pickle * Minor updates. * Change _accelerate_num_step_called to _accelerate_step_called --------- Co-authored-by: YU Xinyuan <yuxinyuan02@corp.netease.com>