when destroy should be called

[vipcxj]

I found a destry function and just know that it can be used to clean up resources. There is nothing else described in the documentation.
So does this function have to be executed and is there a self-cleaning mechanism for the resolver object? The documentation strongly recommends that the resolver object must be initialized as a local variable in the function, meaning that it is scoped to the function. But I don't see destroy being called in any of the examples. Is it not required to be called? I think that since the function was added, it should state its application scenario, otherwise it could be misleading