@Override
    public synchronized Uuid clientInstanceId(Duration timeout) {
        if (clientInstanceId == null) {
            throw new UnsupportedOperationException("clientInstanceId not set");
        }

        return clientInstanceId;
    }
A mock of the {@link ShareConsumer} interface you can use for testing code that uses Kafka. This class is <i> not
thread-safe </i>.
clients/src/main/java/org/apache/kafka/clients/consumer/MockShareConsumer.java