code: public boolean stop() {
          if (!this.isStarted.get() || !this.isStopped.compareAndSet(false, true)) {
              return false;
          }
          this.timer.shutdown();
          LogWatchStorageSweeper.LOGGER.info("Cancelled automated unreachable message sweep in {}.",
                  this.messaging.getLogWatch());
          return true;
      }
docs: Stop the sweeping if not stopped already.
  
  @return False if {@link #start()} not called or {@link #stop()} called
  already.