PHPMailer\PHPMailer\SMTP::quit PHP Метод

    public function quit($close_on_error = true)
    {
        $noerror = $this->sendCommand('QUIT', 'QUIT', 221);
        $err = $this->error;
        //Save any error
        if ($noerror or $close_on_error) {
            $this->close();
            $this->error = $err;
            //Restore any error from the quit command
        }
        return $noerror;
    }