In InventoryCosArmor There is a duplicate method signature error when using forge mappings, as IInvetory#getItem(int) from official mappings, maps to IInventory#getStackInSlot(int) which clashes with IItemHandler#getStackInSlot(int) causing a loading error in dev environments that use forge mappings.

I was hoping that you'd be able to remove InventoryCosArmor#getStackInSlot(int) as it looks like its not needed there, which should fix this problem.

Thanks!