How to implement Basic publish/subscribe messaging using swift

Hello,
Is there is a swift example for publish/subscribe messaging ?
I found the following link in one of the articles but it is not public :
https://backendless.com/feature-65-basic-publishsubscribe-messaging/?preview=true&preview_id=3224&preview_nonce=baad99b69f

I also want to ask if the service requires any set up/ certificates like push notification ?

regards,

You could download BlogFeatureDay project from our github.

Here is publish/subscribe sample.

Publish/subscribe don’t need any additional settings & certificates.