code: public void run() throws Exception {
      if (config == null) {
        return;
      }
      config.channels = 1;
      config.directExecutor = true;
      ManagedChannel ch = config.newChannel();
      SimpleRequest req = config.newRequest();
      LoadGenerationWorker worker =
          new LoadGenerationWorker(ch, req, config.targetQps, config.duration);
      final long start = System.nanoTime();
      Histogram histogram = worker.call();
      final long end = System.nanoTime();
      printStats(histogram, end - start);
      if (config.histogramFile != null) {
        saveHistogram(histogram, config.histogramFile);
      }
      ch.shutdown();
    }
docs: Start the open loop client.