Fix closed channel packets

Signed-off-by: Lixfel <agga-games@gmx.de>

FightSystem_Main/src/de/steamwar/fightsystem/fight/Fight.java

@@ -134,6 +134,8 @@ public class Fight {
                 return;
 
             Bukkit.getScheduler().runTaskLater(FightSystem.getPlugin(), () -> {
+                if(!player.isOnline())
+                    return;
                 PacketContainer gm1packet = ProtocolLibrary.getProtocolManager().createPacket(PacketType.Play.Server.PLAYER_INFO);
                 gm1packet.getPlayerInfoAction().write(0, EnumWrappers.PlayerInfoAction.UPDATE_GAME_MODE);
                 List<PlayerInfoData> playerInfoActions = new ArrayList<>();