public static BlockBasedTableConfig getRocksDBTableFormatConfig(final String groupId, final Class<?> cls) {
        Requires.requireNonNull(cls, "cls");
        String key = buildKey(groupId, cls);
        BlockBasedTableConfig cfg = tableFormatConfigTable.get(key);
        if (cfg == null) {
            final BlockBasedTableConfig newCfg = getDefaultRocksDBTableConfig();
            cfg = tableFormatConfigTable.putIfAbsent(key, newCfg);
            if (cfg == null) {
                cfg = newCfg;
            }
        }
        return copyTableFormatConfig(cfg);
    }
Get a new default TableFormatConfig or a copy of the exist ableFormatConfig.

@param  groupId raft group id
@param cls the key of TableFormatConfig
@return new default TableFormatConfig or a copy of the exist TableFormatConfig
jraft-core/src/main/java/com/alipay/sofa/jraft/util/StorageOptionsFactory.java