The subscriber prints a message to the console and sets a state variable to indicate it has been called.

订阅者向控制台打印一个消息并且设置一个状态变量以暗示它已经被调用。

youdao

The subscriber prints a message to the console and sets a state variable to indicate it has been called.

订阅者向控制台打印一个消息并且设置一个状态变量以暗示它已经被调用。

youdao