in include/unifex/indexed_for.hpp [169:173]
auto operator()(Sender&& predecessor, Policy&& policy, Range&& range, Func&& func) const
-> _ifor::sender<Sender, Policy, Range, Func> {
return _ifor::sender<Sender, Policy, Range, Func>{
(Sender &&) predecessor, (Policy &&) policy, (Range &&) range, (Func &&) func};
}