code: public Observable<Page<FailoverGroupInner>> listByServerAsync(final String resourceGroupName, final String serverName) {
          return listByServerWithServiceResponseAsync(resourceGroupName, serverName)
              .map(new Func1<ServiceResponse<Page<FailoverGroupInner>>, Page<FailoverGroupInner>>() {
                  @Override
                  public Page<FailoverGroupInner> call(ServiceResponse<Page<FailoverGroupInner>> response) {
                      return response.body();
                  }
              });
      }
docs: Lists the failover groups in a server.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param serverName The name of the server containing the failover group.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;FailoverGroupInner&gt; object