@Override
    public UTF8String getString(int colId) {
        if (rowDataAddr == 0) {
            throw new IllegalStateException("illegal row");
        }
        long offsetAndLen = strOffsetLen(colId);
        int offset = (int) (offsetAndLen >>> 32);
        int len = (int) offsetAndLen & ColumnType.MAX_STRING_UTF8_SIZE_MASK;
        assert len >= 0;
        if (len == 0) {
            return UTF8String.EMPTY_UTF8;
        } else {
            return UTF8String.fromAddress(null, rowDataAddr + offset, len);
        }
    }
The aproximately memeory usage of this object. Currently only return the raw row data size.
indexr-segment/src/main/java/io/indexr/segment/rt/UTF8Row.java