code: func NewMutateResponse(
  	key string,
  	status ResponseStatus,
  	version uint64) MutateResponse {
  
  	resp := &genericResponse{
  		status: status,
  	}
  	resp.item.Key = key
  	if status == StatusNoError {
  		resp.item.DataVersionId = version
  	}
  	return resp
  }
docs: // This creates a normal MutateResponse.