listTunnels method
Lists the caller's active tunnels held by the Hub.
Implementation
Future<List<TunnelInfo>> listTunnels() {
_ensureConnected();
final id = newId();
final completer = Completer<List<TunnelInfo>>();
_pendingTunnelLists[id] = completer;
_connection!.send(ControlFrame(TunnelListRequest(requestId: id)));
return completer.future;
}