code: func (mem DevicePtr) MemSize() uintptr {
  	size, _, err := mem.AddressRange()
  	if err != nil {
  		log.Printf("MEMSIZE ERR %v", err)
  	}
  	return uintptr(size)
  }
docs: // MemSize returns the size of the memory slab in bytes. Returns 0 if errors occured