An application produces large volumes of AWS X-Ray trace data hourly. You want users to filter the returned traces by custom attributes. How should you add custom attributes so they can be used in X-Ray filter expressions?

Annotations are key-value pairs that are indexed by X-Ray and can be used in filter expressions to find traces. This makes them ideal for filtering large volumes of trace data by custom attributes. Metadata, while also key-value pairs, are not indexed and cannot be used in filter expressions; they are for storing additional, unindexed information. Adding custom attributes as new segment fields is not a standard or supported X-Ray feature for filtering. Creating new sampling rules based on custom attributes would affect which traces are recorded, not how existing recorded traces are filtered.