message: Clarify time unit in grappler ChannelCostEstimator and VirtualScheduler.
diff: @@ -1022,7 +1022,8 @@ Costs VirtualScheduler::Summary() const {
  bool is_cost_accurate;
  std::tie(cost, is_cost_accurate) = op_costs_.at(item.first);
  VLOG(2) << "Node: " << item.first << ", Count: " << item.second
  - << ", Individual Cost: " << (is_cost_accurate ? "" : "~") << cost;
  + << ", Individual Cost: " << (is_cost_accurate ? "" : "~") << cost
  + << " us";
  }
  }
  