Method operation

include/exec/libdispatch_queue.hpp:214–235

      Receiver           receiver;

      operation(libdispatch_queue *queue_arg, Receiver rcvr)
        : queue(*queue_arg)
        , receiver(std::move(rcvr))
      {
        this->execute = [](task_base *t) noexcept
        {
          auto &op     = *static_cast<operation *>(t);
          auto  stoken = STDEXEC::get_stop_token(STDEXEC::get_env(op.receiver));
          if constexpr (STDEXEC::unstoppable_token<decltype(stoken)>)
          {
            STDEXEC::set_value(std::move(op.receiver));
          }
          else if (stoken.stop_requested())
          {
            STDEXEC::set_stopped(std::move(op.receiver));
          }
          else
          {
            STDEXEC::set_value(std::move(op.receiver));
          }
        };
      }

      void enqueue(task_base *op) const
      {