Not the way you should do it.

If I would need to do this, i would use something like rabbitmq and persistent storage.

So your message comes to probot and you store the message with a timeout into a not consumed queue of rabbitmq. The queue has a DeadLetterExchange. So when the timeout of the message is happening, the messagee comes to the DeadLetterExchange and puts it into a second queue without the timeout or a bigger timeout to clean the queue.

You consume the second queue in your app and voilá you have your delayed processing. You need to manually create a Octokit Object via the Github App id and secret.

You can do it probably with similar tech like google pubsub. But I dont have a clue how to do it differently. The benefit of rabbitmq would be that you reduce the chance of loosing messages and also rabbitmq can be assigned more RAM.

You can of course store the messsages in memory of your probot instance... but that will probably be leaky and error prone.