<< " instances";
    }
  }

  struct EdgeInfo {
    absl::string_view node_name;
    std::optional<absl::string_view> cluster_name;

    absl::string_view GetClusterName() const {
      return cluster_name ? *cluster_name : "[none]";
    }

    std::pair<absl::string_view, std::optional<absl::string_view>> AsPair()
        const {
      return {node_name, cluster_name};