Add C# / .NET example

[dveeden]

What is changed, added or deleted? (Required)

Add example with C#

Which TiDB version(s) do your changes apply to? (Required)

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

For details, see tips for choosing the affected versions.

• [x] master (the latest development version)
• [x] v9.0 (TiDB 9.0 versions)
• [x] v8.5 (TiDB 8.5 versions)
• [ ] v8.4 (TiDB 8.4 versions)
• [ ] v8.3 (TiDB 8.3 versions)
• [ ] v8.1 (TiDB 8.1 versions)
• [ ] v7.5 (TiDB 7.5 versions)
• [ ] v7.1 (TiDB 7.1 versions)
• [ ] v6.5 (TiDB 6.5 versions)
• [ ] v6.1 (TiDB 6.1 versions)
• [ ] v5.4 (TiDB 5.4 versions)

What is the related PR or file link(s)?

• This PR is translated from:
• Other reference link(s):

Do your changes match any of the following descriptions?

• [ ] Delete files
• [ ] Change aliases
• [ ] Need modification after applied to another branch
• [ ] Might cause conflicts after applied to another branch

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-06-25 03:45:31.399633653 +0000 UTC m=+848184.122812635: :ballot_box_with_check: agreed by hfxsd.
• 2025-06-25 10:14:40.81519756 +0000 UTC m=+871533.538376543: :ballot_box_with_check: agreed by lilin90.

[ti-chi-bot[bot]]

@mjonss: adding LGTM is restricted to approvers and reviewers in OWNERS files.

In response to this:

LGTM, tested in a Linux environment

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[hfxsd]

/approve

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hfxsd

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• ~~OWNERS~~ [hfxsd]

Approvers can indicate their approval by writing /approve in a comment Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.5: #21274.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-cloud: #21280. But this PR has conflicts, please resolve them!

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #21281. But this PR has conflicts, please resolve them!

[ti-chi-bot]

In response to a cherrypick label: new pull request could not be created: failed to create pull request against pingcap/docs#release-cloud from head ti-chi-bot:cherry-pick-21206-to-release-cloud: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"A pull request already exists for ti-chi-bot:cherry-pick-21206-to-release-cloud."}],"documentation_url":"https://docs.github.com/rest/pulls/pulls#create-a-pull-request","status":"422"}