list method
Returns descriptors for discovery, applying an optional label filter
(each key=value must match the node's labels).
Implementation
List<NodeDescriptor> list({Map<String, String> filter = const {}}) {
final result = <NodeDescriptor>[];
for (final node in _byId.values) {
if (_matches(node.descriptor, filter)) result.add(node.descriptor);
}
result.sort((a, b) => a.id.value.compareTo(b.id.value));
return result;
}