code: public Observable<ServiceResponse<Page<P2SVpnServerConfigurationInner>>> listByVirtualWanSinglePageAsync(final String resourceGroupName, final String virtualWanName) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (virtualWanName == null) {
              throw new IllegalArgumentException("Parameter virtualWanName is required and cannot be null.");
          }
          final String apiVersion = "2018-08-01";
          return service.listByVirtualWan(this.client.subscriptionId(), resourceGroupName, virtualWanName, apiVersion, this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Page<P2SVpnServerConfigurationInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<P2SVpnServerConfigurationInner>>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<PageImpl<P2SVpnServerConfigurationInner>> result = listByVirtualWanDelegate(response);
                          return Observable.just(new ServiceResponse<Page<P2SVpnServerConfigurationInner>>(result.body(), result.response()));
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Retrieves all P2SVpnServerConfigurations for a particular VirtualWan.
  
  ServiceResponse<PageImpl<P2SVpnServerConfigurationInner>> * @param resourceGroupName The resource group name of the VirtualWan.
  ServiceResponse<PageImpl<P2SVpnServerConfigurationInner>> * @param virtualWanName The name of the VirtualWan.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the PagedList&lt;P2SVpnServerConfigurationInner&gt; object wrapped in {@link ServiceResponse} if successful.