code: public Observable<LocalNetworkGatewayInner> getByResourceGroupAsync(String resourceGroupName, String localNetworkGatewayName) {
          return getByResourceGroupWithServiceResponseAsync(resourceGroupName, localNetworkGatewayName).map(new Func1<ServiceResponse<LocalNetworkGatewayInner>, LocalNetworkGatewayInner>() {
              @Override
              public LocalNetworkGatewayInner call(ServiceResponse<LocalNetworkGatewayInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets the specified local network gateway in a resource group.
  
  @param resourceGroupName The name of the resource group.
  @param localNetworkGatewayName The name of the local network gateway.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the LocalNetworkGatewayInner object