readTuple method
Implementation
Uint8List? readTuple(int slotIdx) {
if (slotIdx < 0 || slotIdx >= slotCount) return null;
if (!isAlive(slotIdx)) return null; // tombstone
final off = _slotTupleOffset(slotIdx);
final len = _slotTupleLength(slotIdx);
if (off < PageConst.headerSize || off + len > PageConst.pageSize) return null;
return Uint8List.fromList(_buf.sublist(off, off + len));
}