private static String noClientId() {
        throw new UnsupportedOperationException("This offset store should not instantiate any Kafka clients");
    }
Build a connector-specific offset store with read-only support. The consumer will be {@link Consumer#close(Duration) closed}
when this store is {@link #stop() stopped}, but the topic admin must be {@link TopicAdmin#close(Duration) closed} by the caller.
@param topic the name of the offsets topic to use
@param consumer the consumer to use for reading from the offsets topic
@param topicAdmin the topic admin to use for creating and querying metadata for the offsets topic
@param keyConverter the worker's internal key converter that can be used to deserialize offset keys from the {@link KafkaBasedLog}
@return a read-only offset store backed by the given topic and Kafka clients
connect/runtime/src/main/java/org/apache/kafka/connect/storage/KafkaOffsetBackingStore.java