code: public Observable<Page<SnapshotInner>> listByResourceGroupAsync(final String resourceGroupName) {
          return listByResourceGroupWithServiceResponseAsync(resourceGroupName)
              .map(new Func1<ServiceResponse<Page<SnapshotInner>>, Page<SnapshotInner>>() {
                  @Override
                  public Page<SnapshotInner> call(ServiceResponse<Page<SnapshotInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists snapshots under a resource group.
  
  @param resourceGroupName The name of the resource group.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;SnapshotInner&gt; object