How to correctly specify number of workers?

[volico]

How to specify number of workers?
I tried using --api-workers in bentoml serve, but it seems that it doesn't make any difference.
Here is screenshot of my experiment with one of examples:

I added print in serve.py and I can see multiple prints even if I specify number of api-workers=1. I observe this behaviour on other examples as welI. I also tried to set number of workers in configuration:

version: 1
api_server:
  workers: 1
runners:
  resources:
    cpu: 1
  workers_per_resource: 1

But it didn't help either.

How should I correctly specify number of workers?