@Override
        public Key createKey(final Key parentKey,
                             final StoredValues storedValues,
                             final ByteBuffer keyBuffer) {
            if (parentKey.getDepth() > 0) {
                throw new RuntimeException("Unexpected parent key");
            }
            final long timeMs = storedValueKeyFactory.getTimeMs(storedValues);
            try (final Input input = new ByteBufferInput(keyBuffer.duplicate())) {
                final long uniqueId = input.readLong();
                return new Key(timeMs, List.of(new UngroupedKeyPart(uniqueId)));
            }
        }
Creates flat time based unique key. <TIME_MS><UNIQUE_ID>
stroom-query/stroom-query-common/src/main/java/stroom/query/common/v2/LmdbRowKeyFactoryFactory.java