int LuaShell::TimedCall(lua_State* L)
{
    luaL_argcheck(L, lua_type(L, 1) == LUA_TFUNCTION, 1, "setTimeout requires a function.");
    double timeout = luaL_checknumber(L, 2);

    lua_State* globalL = lua_getstate(L);
    RegValue v = lua_toregvalue(L, -1);
    TimeManager::getSingleton().SetTimeout([globalL, v](double t)->double {
        try
        {
            lua_pushregvalue(globalL, v);
            return lua_tcall<double, double>(globalL, t);
        }
        catch (const std::exception& ex)
        {
            // log something.
            return -1;
        }
    }, timeout);
    return 0;
}