Value fetch(int foundAt, Value value) {
        if ((foundAt & EXACT_MASK) == 0) {
            value.clear();
        } else {
            Debug.$assert0.t(foundAt > 0 && (foundAt & P_MASK) < _keyBlockEnd);
            int kbData = getInt(foundAt & P_MASK);
            int tail = decodeKeyBlockTail(kbData);
            int tbData = getInt(tail);
            int klength = decodeTailBlockKLength(tbData);
            int size = decodeTailBlockSize(tbData);
            int valueSize = size - klength - _tailHeaderSize;
            value.putEncodedBytes(_bytes, tail + _tailHeaderSize + klength, valueSize);
        }
        return value;
    }