PHPMailer\PHPMailer\PHPMailer::getLastMessageID PHP Метод

getLastMessageID() публичный метод

Technically this is the value from the last time the headers were created, but it's also the message ID of the last sent message except in pathological cases.
public getLastMessageID ( ) : string
Результат string
    public function getLastMessageID()
    {
        return $this->lastMessageID;
    }