code: public ServiceFuture<List<SiteInner>> listWebAppsAsync(final String resourceGroupName, final String name, final String skipToken, final String filter, final String top, final ListOperationCallback<SiteInner> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              listWebAppsSinglePageAsync(resourceGroupName, name, skipToken, filter, top),
              new Func1<String, Observable<ServiceResponse<Page<SiteInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<SiteInner>>> call(String nextPageLink) {
                      return listWebAppsNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Get all apps associated with an App Service plan.
  Get all apps associated with an App Service plan.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of the App Service plan.
  @param skipToken Skip to a web app in the list of webapps associated with app service plan. If specified, the resulting list will contain web apps starting from (including) the skipToken. Otherwise, the resulting list contains web apps from the start of the list
  @param filter Supported filter: $filter=state eq running. Returns only web apps that are currently running
  @param top List page size. If specified, results are paged.
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object