public int valCount() {
        return count;
    }
The ByteBuffer here is normally comes from {@link java.nio.channels.FileChannel#map(FileChannel.MapMode, long, long)}.
If it is a pure memory byte reader, then you probably should use {@link StringsStruct}.
indexr-common/src/main/java/io/indexr/data/StringsStructOnByteBufferReader.java