[akvelon][tour-of-beam] backend bootstraps

[eantyshev]

Please add a meaningful description for your change here

---

addresses #22571

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• [ ] Choose reviewer(s) and mention them in a comment (R: @username).
• [ ] Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• [ ] Update CHANGES.md with noteworthy changes.
• [ ] If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI.

[github-actions[bot]]

Assigning reviewers. If you would like to opt out of this review, comment assign to next reviewer:

R: @damccorm for label build.

Available commands:

• stop reviewer notifications - opt out of the automated review tooling
• remind me after tests pass - tag the comment author after tests pass
• waiting on author - shift the attention set back to the author (any comment or push by the author will return the attention set to the reviewers)

The PR bot will only process comments in the main thread (not review comments).

[codecov[bot]]

Codecov Report

Merging #22556 (4e58de6) into master (48b5349) will increase coverage by 9.33%. The diff coverage is n/a.

:exclamation: Current head 4e58de6 differs from pull request most recent head 0ebdcaf. Consider uploading reports for the commit 0ebdcaf to get more accurate results

@@            Coverage Diff             @@
##           master   #22556      +/-   ##
==========================================
+ Coverage   74.17%   83.50%   +9.33%     
==========================================
  Files         706      477     -229     
  Lines       93229    66214   -27015     
==========================================
- Hits        69148    55291   -13857     
+ Misses      22813    10923   -11890     
+ Partials     1268        0    -1268     

Flag	Coverage Δ
go	?
python	83.50% <ø> (-0.04%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...examples/inference/sklearn_mnist_classification.py	43.75% <0.00%> (-3.75%)	:arrow_down:
sdks/python/apache_beam/utils/subprocess_server.py	56.54% <0.00%> (-2.20%)	:arrow_down:
sdks/python/apache_beam/internal/metrics/metric.py	93.00% <0.00%> (-1.00%)	:arrow_down:
...eam/runners/portability/fn_api_runner/execution.py	92.44% <0.00%> (-0.65%)	:arrow_down:
sdks/python/apache_beam/coders/coders.py	88.00% <0.00%> (-0.35%)	:arrow_down:
sdks/python/apache_beam/io/fileio.py	95.98% <0.00%> (-0.28%)	:arrow_down:
...s/python/apache_beam/examples/wordcount_minimal.py	92.59% <0.00%> (-0.27%)	:arrow_down:
sdks/python/apache_beam/typehints/schemas.py	94.15% <0.00%> (-0.17%)	:arrow_down:
...thon/apache_beam/ml/inference/sklearn_inference.py	95.08% <0.00%> (-0.16%)	:arrow_down:
sdks/python/apache_beam/runners/common.py	88.59% <0.00%> (-0.13%)	:arrow_down:
... and 261 more

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more

[olehborysevych]

R: @damccorm

[github-actions[bot]]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control