...

The change of the StateStoreContext interface does not require any changes to any of the implementations of the interface, it merely exposes (recordMetadata) a method that is already implemented in AbstractProcessorContext. Therefore we do not expect any compatibility issues. Moreover, recordMetadata returns an object of type RecordMetadata which is exclusively read-only, thus, protecting Kafka-internal from being tampered by applications. 

Rejected Alternatives

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Add a new Put mehtod to the KeyValueStore interface

The idea would be to couple data and metadata together in a single Put call. 

public interface KeyValueStore<K, V> extends StateStore, ReadOnlyKeyValueStore<K, V> {
	...


	void Put(K key, V value, RecordMetadata metadata);

	...
}

Add a new UpdatePosition method to the KeyValueStore interface

public interface KeyValueStore<K, V> extends StateStore, ReadOnlyKeyValueStore<K, V> {
	...


	void UpdatePosition(String topic, int partition, int offset);

	...
}