code: public Observable<UserInner> beginCreateOrUpdateAsync(String deviceName, String name, String resourceGroupName, UserInner user) {
          return beginCreateOrUpdateWithServiceResponseAsync(deviceName, name, resourceGroupName, user).map(new Func1<ServiceResponse<UserInner>, UserInner>() {
              @Override
              public UserInner call(ServiceResponse<UserInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates a new user or updates an existing user's information on a data box edge/gateway device.
  
  @param deviceName The device name.
  @param name The user name.
  @param resourceGroupName The resource group name.
  @param user The user details.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the UserInner object