getProperties method
override
    Properties of this DiagnosticsNode.
Properties and children are kept distinct even though they are both List<DiagnosticsNode> because they should be grouped differently.
Implementation
@override
List<DiagnosticsNode> getProperties() {
  if (expandableValue) {
    final T? object = value;
    if (object is DiagnosticsNode) {
      return object.getProperties();
    }
    if (object is Diagnosticable) {
      return object.toDiagnosticsNode(style: style).getProperties();
    }
  }
  return const <DiagnosticsNode>[];
}