Method ping

3rdparty/libprocess/src/tests/benchmarks.cpp:237–245

private:
  void ping(const UPID& from, const string& body)
  {
    if (!links.contains(from)) {
      link(from);
      links.insert(from);
    }

    send(from, "pong", body.c_str(), body.size());
  }

  hashset<UPID> links;
};