OnBattleStarted onBattleStarted = (TUIBattleInfo battleInfo) {};

OnBattleEnded onBattleEnded = (TUIBattleInfo battleInfo, TUIBattleStoppedReason reason) {};

OnUserJoinBattle onUserJoinBattle = (String battleId, TUIBattleUser battleUser) {};

OnUserExitBattle onUserExitBattle = (String battleId, TUIBattleUser battleUser) {};

OnBattleScoreChanged onBattleScoreChanged = (String battleId, List<TUIBattleUser> battleUserList) {};

OnBattleRequestReceived onBattleRequestReceived = 
    (TUIBattleInfo battleInfo, 
     TUIBattleUser inviter, 
     TUIBattleUser invitee) {};

OnBattleRequestCancelled onBattleRequestCancelled = 
    (TUIBattleInfo battleInfo, 
     TUIBattleUser inviter, 
     TUIBattleUser invitee) {};

OnBattleRequestTimeout onBattleRequestTimeout = 
    (TUIBattleInfo battleInfo, 
     TUIBattleUser inviter, 
     TUIBattleUser invitee) {};

OnBattleRequestAccept onBattleRequestAccept = 
    (TUIBattleInfo battleInfo, 
     TUIBattleUser inviter, 
     TUIBattleUser invitee) {};

OnBattleRequestReject onBattleRequestAccept = 
    (TUIBattleInfo battleInfo, 
     TUIBattleUser inviter, 
     TUIBattleUser invitee) {};

 void addObserver(TUILiveBattleObserver observer);

void removeObserver(TUILiveBattleObserver observer);

Future<TUIValueCallBack<TUIBattleRequestResult>> requestBattle
    (TUIBattleConfig config, 
     List<String> userIdList, 
     int timeout);

Future<TUIActionCallback> cancelBattleRequest(String battleId, List<String> userIdList);

Future<TUIActionCallback> acceptBattle(String battleId);

Future<TUIActionCallback> rejectBattle(String battleId);

Future<TUIActionCallback> exitBattle(String battleId);