For sending mail we configure Smtp transport. But for transport is enough to get properly configured protocol object. It work:

        $transport = new SmtpTransport(new SmtpOptions(array(
            'name'             => 'gmail',
            'host'             => 'smtp.gmail.com',
            'port'             => 465,
            'connectionClass'  => 'login',
            'connectionConfig' => array(
                'ssl'      => 'ssl',
                'username' => 'user',
                'password' => 'pass',
            )
        )));
        $transport->send($message);

It don't work but should:

        $transport = new SmtpTransport(new SmtpOptions(array(
            'name'             => 'gmail',
            'connectionClass'  => 'login',
            'connectionConfig' => array(
                'ssl'      => 'ssl',
                'host'     => 'smtp.gmail.com',
                'port'     => 465,
                'username' => 'user',
                'password' => 'pass',
            )
        )));
        $transport->send($message);

Zend\Mail\Transport\Smtp:send() use only connection protocol. I guess class SmtpOptions is wasted. It's enough Protocols classes, or them should get configs from SmtpOptions class.