Creates multiple custom events in a single request.
Valid events are processed together for better performance - they are then returned in the successful list in the response.
Events that were parsed as invalid are returned separately in the response - in the failed list in the response.
If there are bottlenecks in processing the events due to unforeseen circumstances, they will be queued for async processing.
The queued events will be returned in the queued list in the response.
Returns 201 when all events are successfully created.
Returns 202 when all events are queued for async processing.
Returns 201 for mixed results (some successful, some queued, or some failed).
Returning mixed results can happen if during the bulk processing of events, some events are successfully processed,
some are queued for async processing.
If there are invalid events in the payload, the whole payload wouldn't be processed and a 422 response is expected.
Therefore, the failed list in the response should always be empty, but it is kept there for completeness.