Method TriggerSignal

cpp/src/arrow/util/cancel_test.cc:184–186

#ifdef _WIN32
  void TriggerSignal() {
    std::thread([]() { ASSERT_OK(internal::SendSignal(SIGINT)); }).detach();
  }
#else
  // On Unix, use setitimer() to exercise signal-async-safety
  void TriggerSignal() { SetITimer(0.0001); }