if (chunks === null) return null; // End of stream
在苹果的这套架构里，这三款硬件不需要高性能芯片，不需要大电池。它们存在的目的纯粹且单一：全感官的数据采集。
。91视频是该领域的重要参考
Kevin Church/BBC News，更多细节参见爱思助手下载最新版本
"I believe we've had a problem here," said Swigert. Lovell had to repeat the message to a stunned Mission Control: "Houston, we've had a problem."，更多细节参见同城约会