docs: public void stop() {
          try {
              Stopwatch watch = Stopwatch.createStarted();
              stopAsync();
              log.info("Awaiting PeerGroup shutdown ...");
              executor.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);
              log.info("... took {}", watch);
          } catch (InterruptedException e) {
              throw new RuntimeException(e);
          }
      }