In other words, this means that the old memory model made promises only about the visibility of the variable being read or written, and no promises about the visibility of writes to other variables.
换句话说，这意味着老的内存模型只保证正在读或写的变量的可见性，不保证写入其他变量的可见性。
2
To declare a static property, place the keyword static after the visibility modifier, directly in front of the property variable.
要声明静态属性，将关键字static放在可见度修饰符后面，直接位于属性变量前面。
3
Clicking the Make Visibility Dynamic button creates a Visibilityvariable.