开发人员编写代码来通过API访问设备，但是一些API目前不可用，比如一个指针api、一个视频API或一个套接字api。

Developers write code to access the device through its APIs, but some APIs are not yet available, such as a compass API, a video API, or a sockets API.

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这就意味着在comet流样式通信持续期间，从客户端设备到后端服务器的每个系统上都至少有一个连接处于不可用状态。

This means that during the duration of a Comet streaming style communication, at least one connection is tied up on each system from the client device to the backend server.

youdao

这个新的设计被用于数据中心冷却技术的补充，或者是当这些设备位于新鲜空气不可用的情况下。

The new design could be used as supplemental cooling in a data center using free cooling, or in facilities located in areas where fresh air cooling isn't feasible.

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