@Override
    protected InLongMsgHead parseHead(String attr) {
        return InLongMsgKvUtils.parseHead(attr);
    }
True if the predefinedField existed, default true.
inlong-sort/sort-formats/format-row/format-inlongmsg-kv/src/main/java/org/apache/inlong/sort/formats/inlongmsgkv/InLongMsgKvFormatDeserializer.java