private static byte[] serializeLongToBytes(final long l) {
        return ByteBuffer.allocate(Long.BYTES).putLong(l).array();
    }
Converts a {@link KeyValueIterator} which returns keys with prefixes to one which
returns un-prefixed keys.
streams/src/main/java/org/apache/kafka/streams/state/internals/LogicalKeyValueSegment.java