Fix: timer is already cancelled.

src/main/java/emu/grasscutter/game/managers/StaminaManager/StaminaManager.java

@@ -29,9 +29,7 @@ public class StaminaManager {
     private Position previousCoordinates = new Position(0, 0, 0);
     private MotionState currentState = MotionState.MOTION_STANDBY;
     private MotionState previousState = MotionState.MOTION_STANDBY;
-    private final Timer sustainedStaminaHandlerTimer = new Timer();
-    private final SustainedStaminaHandler handleSustainedStamina = new SustainedStaminaHandler();
-    private boolean timerRunning = false;
+    private Timer sustainedStaminaHandlerTimer;
     private GameSession cachedSession = null;
     private GameEntity cachedEntity = null;
     private int staminaRecoverDelay = 0;
@@ -136,21 +134,21 @@ public class StaminaManager {
         entity.getWorld().broadcastPacket(new PacketEntityFightPropUpdateNotify(entity, FightProperty.FIGHT_PROP_CUR_HP));
         entity.getWorld().broadcastPacket(new PacketLifeStateChangeNotify(0, entity, LifeState.LIFE_DEAD));
         player.getScene().removeEntity(entity);
-        ((EntityAvatar)entity).onDeath(dieType, 0);
+        ((EntityAvatar) entity).onDeath(dieType, 0);
     }
 
     public void startSustainedStaminaHandler() {
-        if (!player.isPaused() && !timerRunning) {
-            timerRunning = true;
-            sustainedStaminaHandlerTimer.scheduleAtFixedRate(handleSustainedStamina, 0, 200);
+        if (!player.isPaused() && sustainedStaminaHandlerTimer == null) {
+            sustainedStaminaHandlerTimer = new Timer();
+            sustainedStaminaHandlerTimer.scheduleAtFixedRate(new SustainedStaminaHandler(), 0, 200);
             // Grasscutter.getLogger().debug("[MovementManager] SustainedStaminaHandlerTimer started");
         }
     }
 
     public void stopSustainedStaminaHandler() {
-        if (timerRunning) {
-            timerRunning = false;
+        if (sustainedStaminaHandlerTimer != null) {
             sustainedStaminaHandlerTimer.cancel();
+            sustainedStaminaHandlerTimer = null;
             // Grasscutter.getLogger().debug("[MovementManager] SustainedStaminaHandlerTimer stopped");
         }
     }