code: public ServiceFuture<List<PolicyDefinitionInner>> listBuiltInAsync(final ListOperationCallback<PolicyDefinitionInner> serviceCallback) {
          return AzureServiceFuture.fromPageResponse(
              listBuiltInSinglePageAsync(),
              new Func1<String, Observable<ServiceResponse<Page<PolicyDefinitionInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<PolicyDefinitionInner>>> call(String nextPageLink) {
                      return listBuiltInNextSinglePageAsync(nextPageLink);
                  }
              },
              serviceCallback);
      }
docs: Gets all the built in policy definitions.
  
  @param serviceCallback the async ServiceCallback to handle successful and failed responses.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the {@link ServiceFuture} object