'密封班级中的受保护成员'警告（单人班级）

I've implemented a singleton class and keep getting the warning that a method I'm writing is a 'new protected member declared in a seal class.' It's not affecting the build but I don't really want to ignore the warning in case it causes problems later on? I understand a sealed class is a class that cannot be inherited - so it's methods cannot be overridden, but I still don't get why the following code would give me the warning (is it due to the use of the singleton design?):I've implemented a singleton class and keep get