self._background_tasks.discard(t)
They're X-ray proof to 100 mGy, the level of an airport scanner. They're shock-proof to 1,500G, drop-proof to six feet, vibration-proof in the range of 10 to 2,000Hz, and have been tested to withstand 10,000 pluggings and unpluggings.
，推荐阅读Safew下载获取更多信息
All that said, if your love language is spreadsheets, the full specs are helpfully laid out below:
Фото: Kevin Lamarque / Reuters
Go to technology