Webhooks PR target branch updated event floods queue causing events to get dropped

Issue Summary

This is reproducible on Data Center: yes

The PR target branch updated webhook event will trigger an individual webhook request for each individual PR targeting the updated branch. For medium-large repositories with a decent number of PRs targeting the same branch (e.g. master) this has the potential to flood the webhooks queue each time the given branch is updated. This is causing a large number of webhook requests to get dropped frequently.

Due to performance concerns, we have disabled the event and back-ported it to all affected versions. Ticket will remain open until a long-term solution is implemented.

Expected Results

All webhook requests are sent successfully.

Actual Results

A large number of webhook requests are getting dropped from the queue and hence, are not being sent.

Workaround

Depending on the use case, the PR merged event can be used as an alternative event by checking the target branch in the payload. If the PR merged event does not work for your use case, there is no current work around.