How to use Caffe2:TypeMeta

Question

What is the usage of Caffe2:TypeMeta ? I found this description: TypeMeta is a thin class that allows us to store the type of a container such as a blob, or the data type of a tensor, with a unique run-time id. It also stores some additional data such as the item size and the name of the type for run-time inspection. Definition at line 324 of file typeid.h. TypeMeta is a thin class that allows us to store the type of a container such as a blob, or the data type of a tensor, with a unique run-time id. It also stores some additional data such as the item size and the name of the type for run-time inspection. Definition at line 324 of file typeid.h.

But, really I am not sure how does it work.

In the following example, it gets z.dtype() which is at:Tensor and then it saves it in dtype as caffe2::TypeMeta .

    caffe2::TypeMeta dtype;
    z = torch::rand({1,4});
    dtype = z.dtype();

Not sure what is the point of that and how it is possible to get the data back from dtype as it is done in https://github.com/pytorch/pytorch/blob/master/torch/csrc/api/src/optim/adam.cpp