Why LTable.Len ignore tb.strdict, how can I get the table length set by RawSetString, ForEach Only?

[moxianfeng]

func (tb *LTable) Len() int {
	if tb.array == nil {
		return 0
	}
	var prev LValue = LNil
	for i := len(tb.array) - 1; i >= 0; i-- {
		v := tb.array[i]
		if prev == LNil && v != LNil {
			return i + 1
		}
		prev = v
	}
	return 0
}