code: function resolveClusterTime(topology, $clusterTime) {
    if (topology.clusterTime == null) {
      topology.clusterTime = $clusterTime;
    } else {
      if ($clusterTime.clusterTime.greaterThan(topology.clusterTime.clusterTime)) {
        topology.clusterTime = $clusterTime;
      }
    }
  }
docs: Shared function to determine clusterTime for a given topology
  
  @param {*} topology
  @param {*} clusterTime