请在此测试emoji表情符，或者其他高位字节的汉字，插入后能否成功读取，并验证其消耗的字节数
测试用的字符： aa㡀為😁
测试程序源码
Fatal error: Uncaught PDOException: SQLSTATE[HY000] [2002] Connection refused in /data/web/wp.imysql.com/utf8mb4/utf8mb4.php:64
Stack trace:
#0 /data/web/wp.imysql.com/utf8mb4/utf8mb4.php(64): PDO->__construct()
#1 {main}
thrown in /data/web/wp.imysql.com/utf8mb4/utf8mb4.php on line 64