Heads-Up Notice - Which Side to Scroll

I've noticed that apps that use heads-up notifications can have different behaviors. I always look at my WhatsApp notifications on the left, but my custom SMS app notifications (Textra) should be removed on the right.

I looked at the Notification.Builder documentation but couldn't find anything related to this. Somebody knows?

As a reference, I found an example of how to implement heads-up notification in this section .

EDIT: After testing, a little more comparison of the heads-up notifications of both apps:

• WhatsApp: Swiping left or right can be dismissed and the notification disappears from the notification bar. If I scroll up, it disappears and it keeps the notification in the notification bar.
• Textra: cannot be fired by swinging left. May be dismissed to be verified, but the notification is removed from the panel. The deployment also cancels the heads-up and keeps the notification in the panel.