raft.go
func (r *Raft) setCurrentTerm(t uint64) {
	// Persist to disk first
	if err := r.stable.SetUint64(keyCurrentTerm, t); err != nil {
		panic(fmt.Errorf("failed to save current term: %v", err))
	}
	r.raftState.setCurrentTerm(t)
}
func (r *Raft) setCurrentTerm(t uint64) {
	// Persist to disk first
	if err := r.stable.SetUint64(keyCurrentTerm, t); err != nil {
		panic(fmt.Errorf("failed to save current term: %v", err))
	}
	r.raftState.setCurrentTerm(t)
}
// setCurrentTerm is used to set the current term in a durable manner.