#vulnerable code 
                              @Override
  public String toString() {
    return peer.getId() + "(next=" + nextIndex + ", match=" + matchIndex + "," +
        " attendVote=" + attendVote +
        ", lastRpcSendTime=" + lastRpcSendTime.get().elapsedTimeMs() +
        ", lastRpcResponseTime=" + lastRpcResponseTime.get().elapsedTimeMs() + ")";
  } 
                            #location 3 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                              @Override
  public String toString() {
    return name + "(c" + getCommitIndex() + ",m" + getMatchIndex() + ",n" + getNextIndex()
        + ", attendVote=" + attendVote +
        ", lastRpcSendTime=" + lastRpcSendTime.get().elapsedTimeMs() +
        ", lastRpcResponseTime=" + lastRpcResponseTime.get().elapsedTimeMs() + ")";
  }