anchor.diff:        final List<vm_service.IsolateRef> refs = await _getIsolateRefs();
         for (final vm_service.IsolateRef ref in refs) {
           final vm_service.Isolate isolate = await getIsolateOrNull(ref.id);
  -        if (isolate != null && isolate.extensionRPCs.contains(extensionName)) {
  +        if (isolate != null && isolate.extensionRPCs?.contains(extensionName) == true) {
             return ref;
           }
         }
  
positive.code:   while (socket == null) {
      attempts += 1;
      try {
        socket = await constructor(url, compression: compression);
      } on io.WebSocketException catch (e) {
        await handleError(e);
      } on io.SocketException catch (e) {
  
negative.code:         : <String, String>{},
      );
      if (result != null && result['value'] is String) {
        return result['value'] == 'Brightness.light'
          ? Brightness.light
          : Brightness.dark;
      }
  