Unity报错：error CS0246: The type or namespace name 'Newtonsoft' could not be found (are you missing a using directive or an assembly reference?)

问题描述：error CS0246: The type or namespace name 'Newtonsoft' could not be found (are you missing a using directive or an assembly reference?)

解决方案：通过VS的包管理器添加了Newtonsoft.Json到项目里面。