Set up scaffolding to provide safeaccess to roofs.
设置脚手架，以提供通往屋顶的安全通道。
2
Cage is adopted to provide safeaccess for bolting and testing.
用吊笼以提供螺栓连接和检验的安全通道。
3
Keep in mind that the timer callback function is executed on a worker thread, so you'll want to ensure that you have thread-safeaccess to the state object.