> You can't usefully index a unicode stream in constant time and do correct and useful textual stuff anyway To find an index of a substring you need to scan th

> You can't usefully index a unicode stream in constant time and do correct and useful textual stuff anyway To find an index of a substring you need to scan the string, right. But once you have the byte index you can quickly jump to its position in the string, e.g. when you do a slice operation based on that index: s[i:]. If strings.Index() returned a code point index and not a byte index you would have to scan the string again.