允许用户为离线用户编写消息。

Enable users to write messages for users who are offline.

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每个客户端都可以编写消息，然后广播给所有其他用户。

Each client can write messages that are then broadcast to all other users.

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这降低了解析和编写消息的成本，并且可能改进消息流其他部分中的性能。

This reduces the costs of parsing and writing the message, and might improve performance in other parts of the message flow.

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