Presumably `string_view` is referring to C++ std::string_view ?

It's not holding an "offset", it's a fat pointer, (ptr,len) or possibly (start,end)

You're imagining this as (string_ptr,offset,len) but that's 50% bigger for no practical benefit, you cannot unwind a std::string_view to get the string it's a view into, indeed there may never have been such a string.