[QUESTION]JSON.config(JSONReader.Feature.IgnoreSetNullValue)的作用

*JSON.config(JSONReader.Feature.IgnoreSetNullValue);配置这个的作用*
在新版本中貌似没测试出来该配置的作用，好像配不配置，反序列化结果没啥区别

Start at JSON.config(JSONReader.Feature.IgnoreSetNullValue) and inspect how the option is handled during deserialization. Compare a minimal reproduction with the option enabled and disabled, then check whether existing tests cover the behavior. Done means the option's intended effect is clearly documented or demonstrated by a focused test.

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