Inference API

[cceyda]

Moving the discussion from https://github.com/cceyda/torchserve-dashboard/issues/1#issuecomment-863911194 to here

Current challenges blocking this:

• there is no way to know the format of the expected request/response. Especially for custom handlers.

(I prefer not do model_name->type matching manually)

If a request/response schema is added to the returned OpenAPI definitions, I can probably auto generate something like SwaggerUI.