toJson method
Serialize the built code table. Projectors are regenerated from
(seed, nbits, dim) on load — no need to persist them.
Implementation
Map<String, Object?> toJson(int seed) {
return {
'dim': dim,
'nbits': nbits,
'seed': seed,
'ids': [for (final id in _ids) id],
'codes': base64.encode(_codes.sublist(0, _ids.length * codeSize)),
};
}