code: private void checkState()  {
      Preconditions.checkNotNull(logs);
      if (!contiguous)
        return;
      RemoteEditLog prev = null;
      for (RemoteEditLog log : logs) {
        if (prev != null) {
          if (log.getStartTxId() <= prev.getEndTxId()) {
            throw new IllegalStateException("Invalid log manifest:" + this);
          }
        }
        
        prev = log;
      }
    }
docs: Check that the logs are contiguous and non-overlapping
  sequences of transactions, in sorted order
  @throws IllegalStateException if incorrect