Geyser end of https://github.com/GeyserMC/GeyserOptionalPack/pull/34

core/src/main/java/org/geysermc/geyser/entity/type/LivingEntity.java

@@ -106,6 +106,9 @@ public class LivingEntity extends Entity {
 
         // Riptide spin attack
         setFlag(EntityFlag.DAMAGE_NEARBY_MOBS, (xd & 0x04) == 0x04);
+
+        // OptionalPack usage
+        setFlag(EntityFlag.EMERGING, isUsingItem && isUsingOffhand);
     }
 
     public void setHealth(FloatEntityMetadata entityMetadata) {