code: func (a *arrayBufferLayout) totalBytes() int {
  	if a.total != 0 {
  		return a.total
  	}
  	t := 0
  	for _, p := range a.parts {
  		t += float.SizeInBytes() * p.num
  	}
  	a.total = t
  	return a.total
  }
docs: // totalBytes returns the size in bytes for one element of the array buffer.