code: public UserInner beginCreateOrUpdate(String deviceName, String name, String resourceGroupName, UserInner user) {
          return beginCreateOrUpdateWithServiceResponseAsync(deviceName, name, resourceGroupName, user).toBlocking().single().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
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the UserInner object if successful.