cli-test: more async-friendly / event-driven approach to process monitoring/management

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 6.18557% with 91 lines in your changes are missing coverage. Please review.

Project coverage is 80.41%. Comparing base (0fedf14) to head (02929bb).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1793 +/- ## ========================================== - Coverage 80.73% 80.41% -0.33% ========================================== Files 35 35 Lines 7552 7586 +34 Branches 308 308 ========================================== + Hits 6097 6100 +3 - Misses 1443 1474 +31 Partials 12 12 ``` | [Flag](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/1793/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | Coverage Δ | | |---|---|---| | [cli-hooks](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/1793/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `95.07% <ø> (ø)` | | | [cli-test](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/1793/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `45.47% <6.18%> (-0.89%)` | :arrow_down: | | [webhook](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/1793/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `95.20% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi#carryforward-flags-in-the-pull-request-comment) to find out more.