@Override
    public synchronized byte[] putIfAbsent(final Bytes key, final byte[] value) {
        return physicalStore.putIfAbsent(
            prefixKeyFormatter.addPrefix(key),
            value);
    }
This "logical segment" is a segment which shares its underlying physical store with other
logical segments. Each segment uses a unique, fixed-length key prefix derived from the
segment ID when writing to the shared physical store. In other words, a logical segment
stores a key into a shared physical store by prepending the key with a prefix (unique to
the specific logical segment), and storing the combined key into the physical store.
streams/src/main/java/org/apache/kafka/streams/state/internals/LogicalKeyValueSegment.java