Test with stuff + Forestry potential support

BM_src/forestry/api/storage/BackpackStowEvent.java

@@ -0,0 +1,21 @@
+package forestry.api.storage;
+
+import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.inventory.IInventory;
+import net.minecraft.item.ItemStack;
+import net.minecraftforge.event.Cancelable;
+
+/**
+ * Use @ForgeSubscribe on a method taking this event as an argument. Will fire whenever a backpack tries to store an item. Processing will stop if the stacksize
+ * of stackToStow drops to 0 or less or the event is canceled.
+ */
+@Cancelable
+public class BackpackStowEvent extends BackpackEvent {
+
+	public final ItemStack stackToStow;
+
+	public BackpackStowEvent(EntityPlayer player, IBackpackDefinition backpackDefinition, IInventory backpackInventory, ItemStack stackToStow) {
+		super(player, backpackDefinition, backpackInventory);
+		this.stackToStow = stackToStow;
+	}
+}