code: private void setFollowerState(@Nullable String newLeader) {
          role = Role.FOLLOWER;
  
          setLeader(newLeader);
  
          nextToApplyLogIndex = -1;
          votedServers.clear();
          serverData.clear();
          failAllOutstandingCommands();
  
          scheduleNextElectionTimeout();
      }
docs: DO NOT CALL THIS METHOD DIRECTLY!