首先，对于这个问题，本文中的解决方案的工作原理很好.

First, for this question, the solution in this post Why do I get a "cannot assign" error when setting value to a struct as a value in a map? works perfectly fine.

然后，最后弄清楚为什么在我已经更改为使用指针之后，我的情况仍然无法使用，请参考以下非常简单的代码:

Then, finally figured out why after I already changed to use pointer my case still doesn't work, refer to the below very simple code:

a := make([]int, 3)
fmt.Println(len(a))

b := make(map[string]string, 3)
fmt.Println(len(b))

输出结果如何?我只是以为全部是: 3 ，但是实际上对于地图而言，输出将是 0

What do think the output will be? I simply thought it is all would be: 3, but actually for the map, the output will be 0

然后在地图初始化过程中，我使用了for循环，并使用 len(snapshots)这个值，这意味着初始化过程将永远不会运行...

Then later in the map initialization process, i used a for loop and with this value len(snapshots), that means the initialization process will never get run...

是的，这就是原因.