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