code: func memoryStats() (*memory, error) {
  	mstat := struct {
  		size      uint32
  		_         uint32
  		totalPhys uint64
  		availPhys uint64
  		_         [5]uint64
  	}{}
  
  	// windows sets return value to 0 when function fails.
  	mstat.size = uint32(unsafe.Sizeof(mstat))
  	ret, _, err := procGlobalMemoryStatusEx.Call(uintptr(unsafe.Pointer(&mstat)))
  	if ret == 0 {
  		return nil, err
  	}
  
  	// memoryStats functions from other platforms return memory usage in bytes.
  	return &memory{
  		Usage: mstat.totalPhys - mstat.availPhys,
  		Total: mstat.totalPhys,
  	}, nil
  
  }
docs: // memoryStatus retrieves information about the system's current usage of
  // physical memory.