This class (or a class which this class inherits from) is marked as ‘@immutable‘, but one or more of
搜索到解决方法地址：
https://www.cnblogs.com/110-913-1025/p/11352002.html
经过搜索找到了解决方法，用final修饰
但是final和var 还不能同时修饰，于是就去掉var
This class (or a class which this class inherits from) is marked as ‘@immutable‘, but one or more of
搜索到解决方法地址：
https://www.cnblogs.com/110-913-1025/p/11352002.html
经过搜索找到了解决方法，用final修饰
但是final和var 还不能同时修饰，于是就去掉var