注释中说 leader 维护的 LogIndex 大于当前 Follower 的 LogIndex 代表当前 Follower 失联过，所以 Follower 要告知 Leader 它当前的最大索引，以便下次心跳 Leader 返回。

如果 Follower 失联，leader 收不到 heartbeat reply 是不会更新 nextIndex 的， 也就不会漏发 log entries

Hello. Do you intend to keep updating and maintaining this project? I think it's very interesting and convenient for small projects. I doesn't have any updates really or more commits. I wish I could be maintaining the project, so I would like to talk if it's possible or if not interested, perhaps there's a way for collaboration?

Hi ，
在学习raft过程中发现两个问题：

• 单节点无法选举成功
• leader选举的成功率不高，应该是sendRequestVote中的判断有误，导致现在需要大于（节点数/2+1）个节点赞同才能选举成功

提了PR，麻烦帮忙review