- Skip calling time(nullptr) twice
- Use getter method for m_api instead of exposing it
- Moved api_udate_*() back to private since they're not used anywhere else
Users can pass `--stratum-api` to command line to enable a file called `local/stats` in `--data-api` directory. `local/stats` contains statistics that `StratumServer status` provides but in JSON format. It is currently setup that `local/stats` is updated each time a new job is sent to a worker.