Function isTokenStoppable

test/stdexec/algos/adaptors/test_stop_when.cpp:51–55

  }

  auto isTokenStoppable()
  {
    return ex::read_env(ex::get_stop_token)
         | ex::then([](auto token) noexcept { return token.stop_possible(); });
  }

  TEST_CASE("stop-when substitutes its token when the receiver's token is unstoppable",
            "[adaptors][stop-when]")