divyanshk/BFTRaft: server/serve.go; 42 LoC

Found a possible issue in [divyanshk/BFTRaft](https://www.github.com/divyanshk/BFTRaft) at [server/serve.go](https://github.com/divyanshk/BFTRaft/blob/758edc1249cbe3bc218a6d20f9659b97ac86c0d1/server/serve.go#L451-L492)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first
issue it finds, so please do not limit your consideration to the contents of the below message.

> range-loop variable peer used in defer or goroutine at line 487

[Click here to see the code in its original context.](https://github.com/divyanshk/BFTRaft/blob/758edc1249cbe3bc218a6d20f9659b97ac86c0d1/server/serve.go#L451-L492)

Click here to show the 42 line(s) of Go which triggered the analyzer.

```go
for peer, nextIndex := range state.nextIndex {
votes = make([]*pb.Vote, 0)
// Check if last log index >= nextIndex for a follower
if lastLogIndex >= nextIndex {
// Send AppendEntries RPC with log entries starting at nextIndex
prevLogIndex = nextIndex - 1
entries = state.log[prevLogIndex+1:]
} else {
// Send AppendEntries RPC with empty log entries
prevLogIndex = lastLogIndex
entries = state.log[0:0]
}

prevLogHash = int64(-1)
if prevLogIndex != int64(-1) {
prevLogHash = state.hash[prevLogIndex]
}
// Send heartbeat
log.Printf("Sending %v AppendEntries for nextindex %v", peer, nextIndex)
if !state.proofAccepted[peer] {
votes = state.votes
}
go func(c pb.RaftClient, p string) {
ret, err := c.AppendEntries(
context.Background(),
&pb.AppendEntriesArgs{
Term: state.currentTerm,
LeaderID: id,
PrevLogIndex: prevLogIndex,
PrevLogHash: prevLogHash,
Entries: entries,
Votes: votes,
})
appendResponseChan <- AppendResponse{
ret: ret,
err: err,
peer: p,
prevLogIndex: prevLogIndex,
lengthEntries: int64(len(entries)),
}
}(peerClients[peer], peer)
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 758edc1249cbe3bc218a6d20f9659b97ac86c0d1