rangeAtIndex_ method
Implementation
void rangeAtIndex_(ffi.Pointer<_NSRange> stret, int idx) {
_lib._objc_msgSend_useVariants1
? _lib._objc_msgSend_346_stret(
stret, _id, _lib._sel_rangeAtIndex_1, idx)
: stret.ref =
_lib._objc_msgSend_346(_id, _lib._sel_rangeAtIndex_1, idx);
}