raft.go
func (r *Raft) setLastContact() {
	r.lastContactLock.Lock()
	r.lastContact = time.Now()
	r.lastContactLock.Unlock()
}
func (r *Raft) setLastContact() {
	r.lastContactLock.Lock()
	r.lastContact = time.Now()
	r.lastContactLock.Unlock()
}
// setLastContact is used to set the last contact time to now