Function set_stopped

include/exec/thread_pool_base.hpp:341–345

        }

        void set_stopped() noexcept
        {
          shared_state& state = shared_state_;
          STDEXEC::set_stopped(static_cast<Receiver&&>(state.rcvr_));
        }

        auto get_env() const noexcept -> STDEXEC::env_of_t<Receiver>
        {