public static void compareGroup(ProviderGroup oldGroup, ProviderGroup newGroup,
                                    List<ProviderInfo> add, List<ProviderInfo> remove) {
        final List<ProviderInfo> oldProviders = oldGroup == null ? null : oldGroup.getProviderInfos();
        final List<ProviderInfo> newProviders = newGroup == null ? null : newGroup.getProviderInfos();
        compareProviders(oldProviders, newProviders, add, remove);
    }
Compare two provider group, return add list and remove list

@param oldGroup old provider group
@param newGroup new provider group
@param add      provider list need add
@param remove   provider list need remove
core/api/src/main/java/com/alipay/sofa/rpc/client/ProviderHelper.java