Model construction in Python creates many threads

Hello,

I've been wondering why does the `Model` construction create hundreds of threads which remain idle and are not released?
I can't quite figure out where the forking accrues and how could I join them (and should I even do it)?

The easiest way of replicating it:
```
pip install vosk
python3
from vosk import KaldiRecognizer, Model
model = Model('/path/to/model/')
```
Simply by checking with `htop` I can see that 609 threads have been created and after the `Model` is constructed they are in the sleep state.

Thank you,

Alena Kazakova