docs: private void shutdown() {
  
          // Stop the stats printer, the bid generator and the nibble deleter.
          m_scheduler.shutdown();
  
          try {
              m_scheduler.awaitTermination(60, TimeUnit.SECONDS);
          } catch (InterruptedException e) {
              e.printStackTrace();
          }
  
          try {
              // block until all outstanding txns return
              m_client.drain();
              // close down the client connections
              m_client.close();
          }
          catch (IOException | InterruptedException e) {
              e.printStackTrace();
          }
      }