@Deactivate
  protected void deactivate() {
    if (_clusterChannels != null) {
      for (ClusterChannel clusterChannel : _clusterChannels) {
        clusterChannel.close();
      }
    }

    _localAddresses = null;
    _clusterChannels = null;
    _clusterReceivers = null;

    if (_executorService != null) {
      _executorService.shutdownNow();
    }

    _executorService = null;
  }