replication.go
func updateLastAppended(s *followerReplication, req *AppendEntriesRequest) {
	// Mark any inflight logs as committed
	if logs := req.Entries; len(logs) > 0 {
		last := logs[len(logs)-1]
		s.nextIndex = last.Index + 1
		s.commitment.match(s.peer.ID, last.Index)
	}

	// Notify still leader
	s.notifyAll(true)
}
func updateLastAppended(s *followerReplication, req *AppendEntriesRequest) {
	// Mark any inflight logs as committed
	if logs := req.Entries; len(logs) > 0 {
		last := logs[len(logs)-1]
		s.nextIndex = last.Index + 1
		s.commitment.match(s.peer.ID, last.Index)
	}

	// Notify still leader
	s.notifyAll(true)
}
// updateLastAppended is used to update follower replication state after a
// successful AppendEntries RPC.
// TODO: This isn't used during InstallSnapshot, but the code there is similar.