code: public Observable<PrivateZoneInner> getByResourceGroupAsync(String resourceGroupName, String privateZoneName) {
          return getByResourceGroupWithServiceResponseAsync(resourceGroupName, privateZoneName).map(new Func1<ServiceResponse<PrivateZoneInner>, PrivateZoneInner>() {
              @Override
              public PrivateZoneInner call(ServiceResponse<PrivateZoneInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets a Private DNS zone. Retrieves the zone properties, but not the virtual networks links or the record sets within the zone.
  
  @param resourceGroupName The name of the resource group.
  @param privateZoneName The name of the Private DNS zone (without a terminating dot).
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PrivateZoneInner object