putManySync method
Inserts or replaces several documents with a single WAL frame.
Implementation
void putManySync(List<({Uint8List key, Bytes document})> entries) {
_checkOpen();
if (entries.isEmpty) return;
final ops = <WalOp>[
for (final entry in entries)
WalOp.put(entry.key, entry.document.asUint8List()),
];
applyBatchSync(ops);
}