Configure Swiftmailer for DKIM signature

Does anyone know how to set up the Swiftmailer signer in config? I can see how to do it in the Swiftmailer docs, but I would like to have it in Yii2 config.
…Something like this:

    'mailer' => [
            'class' => 'yii\swiftmailer\Mailer',
            'viewPath' => '@common/mail',
            'class' => 'yii\swiftmailer\Mailer',
            'useFileTransport' => false,
            'transport' => [
                'class' => 'Swift_SmtpTransport',
                'host' => '',
                'username' => 'myusername',
                'password' => 'mypassword',
                'port' => '587',
                'encryption' => 'tls',
                'signCertificate' => ['/path/to/dkim_private_key.pem'],

Did you see this thread? It’s not 100 the same but maybe you need to pass in a different class


Yes, I saw that. That thread also has this comment:

That’s what I want to do. I know it can be done but I’m having trouble finding out how to do it. I want to avoid adding it to every email as shown further down in that thread.