code: public ServiceFuture<Object> getMetadataAsync(String appId, final ServiceCallback<Object> serviceCallback) {
          return ServiceFuture.fromResponse(getMetadataWithServiceResponseAsync(appId), serviceCallback);
      }
docs: Retrieve metric metatadata.
  Gets metadata describing the available metrics.
  
  @param appId ID of the application. This is Application ID from the API Access settings blade in the Azure portal.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object