feat: write column order

[alespour]

Proposed Changes

Adds support for specifying column (tag) order during ingestion via the new tag_order write option. This is primarily intended for the initial write, where sorting tags by query priority can significantly impact query performance:
https://docs.influxdata.com/influxdb3/enterprise/write-data/best-practices/schema-design/#sort-tags-by-query-priority

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• Tests pass
• Commit messages are conventional

[codecov]

Codecov Report

❌ Patch coverage is 97.22222% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.12%. Comparing base (2bfba51) to head (b68c657).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...fluxdb_client_3/write_client/client/write/point.py	97.50%	1 Missing ⚠️
...client/client/write/polars_dataframe_serializer.py	95.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #198      +/-   ##
==========================================
+ Coverage   70.89%   75.12%   +4.22%     
==========================================
  Files          35       35              
  Lines        2388     2420      +32     
==========================================
+ Hits         1693     1818     +125     
+ Misses        695      602      -93     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Copilot]

Pull request overview

Adds a tag_order write option to control tag serialization order in line protocol so users can influence first-write column order (notably for InfluxDB 3 Enterprise schema/query performance considerations).

Changes:

• Introduces tag_order on WriteOptions and threads it through write paths to Point.to_line_protocol(...).
• Updates Point tag serialization to honor a caller-specified tag priority order.
• Adds/updates tests and documentation (README + CHANGELOG) for the new option.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/test_point.py	Adds coverage for tag ordering behavior in Point.to_line_protocol(tag_order=...).
tests/test_influxdb_client_3.py	Verifies WriteOptions.tag_order sanitization/defaults and exercises dict batching path.
influxdb_client_3/write_client/domain/write_precision.py	Marks common model helpers as # pragma: no cover.
influxdb_client_3/write_client/client/write_api.py	Adds tag_order to WriteOptions, sanitizes it, and plumbs it into serialization while filtering it from HTTP kwargs.
influxdb_client_3/write_client/client/write/point.py	Implements ordered tag key selection based on tag_order before falling back to sorted remaining tags.
influxdb_client_3/write_client/client/_base.py	Passes tag_order through _serialize() when serializing Point records.
README.md	Documents how to configure tag_order via WriteOptions.
CHANGELOG.md	Adds a feature entry for tag_order.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

influxdb_client_3/write_client/client/write/polars_dataframe_serializer.py:104

• self.tag_columns is used with + [self.timestamp_column] inside the fields comprehension, which will raise TypeError if callers pass a non-list iterable (e.g., set/tuple) for data_frame_tag_columns. Consider normalizing data_frame_tag_columns to a list in __init__ (or precomputing a set of excluded columns) and using membership checks against that set to avoid both type issues and repeated list allocations per column.

        fields = ",".join(
            f"{col}=\"{self.escape_value(row[self.column_indices[col]])}\"" if isinstance(row[self.column_indices[col]],
                                                                                          str)
            else f"{col}={str(row[self.column_indices[col]]).lower()}" if isinstance(row[self.column_indices[col]],
                                                                                     bool)  # Check for bool first
            else f"{col}={row[self.column_indices[col]]}i" if isinstance(row[self.column_indices[col]], int)
            else f"{col}={row[self.column_indices[col]]}"
            for col in self.column_indices
            if col not in self.tag_columns + [self.timestamp_column] and
            row[self.column_indices[col]] is not None and row[self.column_indices[col]] != ""
        )

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[bednar]

LGTM 🚀