zend framework : set imap mail to read, or move it to a folder

After reading a message's state in Zend_Mail_Storage_Imap with $message->getHeaders(). How do I then set that mail as read?

setHeaders(Zend_Mail_开发者_StackOverflow社区Storage::FLAG_SEEN);

Thanks,

Dan

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$imap = new Zend_Mail_Storage_Imap($config);

$imap->setFlags($message_id,array(Zend_Mail_Storage::FLAG_SEEN));