Request the feature to send metadata in BLS.
**Is your feature request related to a problem? Please describe.**
I want to change the Model according to the BLS input. But BLS requires the same input bach size. So I have to make input like ["model1", "model1"]. If my batch size is 100, should I send 100 same data like ["model1", "model1", "model1"].

**Describe the solution you'd like**
It would be nice to have the feature to send metadata other than batch data.