Gets all event types or a specific event type if name is provided. This is a paginated API. If you provide a null <code>maxResults</code>, this action retrieves a maximum of 10 records per page. If you provide a <code>maxResults</code>, the value must be between 5 and 10. To get the next page results, provide the pagination token from the <code>GetEventTypesResponse</code> as part of your request. A null pagination token fetches the records from the beginning.