Method __wait

include/stdexec/stop_token.hpp:86–98

    constexpr __spin_wait() noexcept = default;

    void __wait() noexcept
    {
      if (__count_++ < __yield_threshold_)
      {
        STDEXEC::__stok::__pause();
      }
      else
      {
        if (__count_ == 0)  // true if __count_ wrapped around
          __count_ = __yield_threshold_;
        std::this_thread::yield();
      }
    }

   private:
    static constexpr uint32_t __yield_threshold_ = 20;