Determine what "Robust Retries" means and how the library should handle them

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At present the Webhook Resource accept method returns the first Entity, however, according to the Robust Retries documentation it is possible that the body may contain multiple entities:

Robust Retries

To ensure that you can rely exclusively on webhooks data, we've put measures in place to make sure your server does not miss a single event.

In case of failed delivery, perhaps due to network problems or server outages on your end, we will store the events and make sure none were lost until your server is back up. Over time, we’ll try to send them to you and re-try your server. The next successful call to your server will include all the past webhooks that accumulated.

Does this mean that the webhook body will be a single JSON API document containing multiple entities (and related data too) or will it be a collection of documents? How does this account for X-PATREON-EVENT? The implementation needs to be determined and then the library can account for this.