zero1 + overlap_comm : Is this correct?

[Suparjie]

Why was the code below removed starting from version v0.13.0?
overlap_comm = False contiguous_gradients = False

DeepSpeed/deepspeed/runtime/engine.py

Line 1486 in c00388a

if zero_stage == ZeroStageEnum.optimizer_states:

Can this ensure correctness during the overlap phase?

DeepSpeed/deepspeed/runtime/zero/stage_1_and_2.py

Line 1317 in c00388a

def reduce_ipg_grads(self):

[tjruwase]

@Suparjie, thanks for the questions. Please see #4887