Php中的IMAP:标记未读/未看到的消息

// 连接到 IMAP 服务器
$mailbox = "{mail.example.com:993/imap/ssl}INBOX";
$username = "your_username";
$password = "your_password";

$connection = imap_open($mailbox, $username, $password)
    or die("Cannot connect: " . imap_last_error());

// 获取邮件的 ID 列表
$email_ids = imap_search($connection, "ALL");

// 标记第一封邮件为未读
$email_id = $email_ids[0];
imap_setflag_full($connection, $email_id, "\\Unseen");

// 关闭连接
imap_close($connection);