### execution::submit

A customisation point that submits a sender to a receiver.

    constexpr unspecified submit = unspecified;

The name `execution::submit` denotes a customisation point object. For some subexpressions `s` and `r`, let `S` be a type such that `decltype((s))` is `S` and let `R` be a type such that `decltype((r))` is `R`. The expression `execution::submit(s, r)` is ill-formed if `sender_to<S, R>` is not `true`. Otherwise, it is expression-equivalent to:

- `s.submit(r)`, if that expression is valid and `S` models `sender`. If the function selected does not submit the receiver object `r` via the sender `s`, the program is ill-formed with no diagnostic required.
- Otherwise, `submit(s, r)`, if that expression is valid and `S` models `sender`, with overload resolution performed in a context that includes the declaration `void submit();` and that does not include a declaration of `execution::submit`. If the function selected by overload resolution does not submit the receiver object `r` via the sender `s`, the program is ill-formed with no diagnostic required.
- Otherwise, `execution::start((new submit_receiver<S, R>{s,r})->state_)`, where `submit_receiver` is an implementation-defined class template equivalent to:

    template<class S, class R>
      struct submit_receiver {
        struct wrap {
          submit_receiver * p_;
          template<class...As>
            requires receiver_of<R, As...>
          void set_value(As&&... as) &&
            noexcept(is_nothrow_receiver_of_v<R, As...>) {
            execution::set_value(std::move(p_->r_), (As&&) as...);
            delete p_;
          }
          template<class E>
            requires receiver<R, E>
          void set_error(E&& e) && noexcept {
            execution::set_error(std::move(p_->r_), (E&&) e);
            delete p_;
          }
          void set_done() && noexcept {
            execution::set_done(std::move(p_->r_));
            delete p_;
          }
        };
        remove_cvref_t<R> r_;
        connect_result_t<S, wrap> state_;
        submit_receiver(S&& s, R&& r)
          : r_((R&&) r)
          , state_(execution::connect((S&&) s, wrap{this})) {}
      };

##### Requirements

Header: `asio/execution/submit.hpp`

Convenience header: `asio/execution.hpp`