...

      public boolean test(final String dummy, final WikiFeed value, final Headers headers) {

          ...

      }

   })

```

And `KeyValue` `RecordContext` will have headers as member to wrap it and pass it to internals.

2. Internal mechanisms to process and store data will be affected by changes on interfaces (e.g. ProcessorContext, RecordCollector, RecordContext, KeyValueStore). This should only affect In Memory and Cache storage, persistent storage like RocksDB should pass-though headers. 

Compatibility, Deprecation, and Migration Plan

...