Mailer SMTP connection

When I place my mail sending in a loop

Will that establish multiple connections to the SMTP server or just one ?

Usually the actual connection creation is pretty slow, so I would love to create 1 connection, then send all the messages

Any ideas ?


        foreach ($arEmails  as $key => $Email)

        {   

            Yii::$app->mailer->compose()

                ->setFrom( $Email->from )

                ->setTo($Email->to)

                ->setSubject($Email->subject)

                ->setHtmlBody($Email->htmlBody)

                ->send();  

}

Transport object is created once so it should be a single connection.