localQuorum method
Find a minimal local quorum for a given node by picking one slice that is fully satisfied within candidates, if any.
Implementation
Set<String>? localQuorum(String node, Set<String> candidates) {
final s = slices[node];
if (s == null) return null;
for (var slice in s) {
if (slice.difference(candidates).isEmpty) return slice;
}
return null;
}