code: public ServiceFuture<Boolean> checkExistenceAsync(String resourceGroupName, final ServiceCallback<Boolean> serviceCallback) {
          return ServiceFuture.fromResponse(checkExistenceWithServiceResponseAsync(resourceGroupName), serviceCallback);
      }
docs: Checks whether a resource group exists.
  
  @param resourceGroupName The name of the resource group to check. The name is case insensitive.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object