[改进] 添加空引用验证，修复插件在服务器完成初始化前的 Failed to run a 2.00 timer in 'DropSurfaceFix v1.0.0' (NullReferenceException: Object reference not set to an instance of an object)报错。
Failed to run a 2.00 timer in 'DropSurfaceFix v1.0.0' (NullReferenceException: Object reference not set to an instance of an object)
