chore: tidy to_unicode() in compat.py

[vparfait]

As part of APMAPI-1159 this is to replace code that supports < python 3.8. Removing comments about the six library as those are outdated. six is a library to assist with python 2/3 compatibility. Kept duck typing for future proofing and to support bytearray.

Checklist

• [X] PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• [x] Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions[bot]]

CODEOWNERS have been resolved as:

ddtrace/internal/compat.py                                              @DataDog/python-guild @DataDog/apm-core-python

[github-actions[bot]]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 268 ± 5 ms.

The average import time from base is: 268 ± 6 ms.

The import time difference between this PR and base is: 0.8 ± 0.2 ms.

Import time breakdown

The following import paths have grown:

ddtrace.auto 0.017 ms (0.01%)

ddtrace 0.017 ms (0.01%)

ddtrace._logger 0.017 ms (0.01%)

ddtrace.internal.telemetry 0.017 ms (0.01%)

ddtrace.internal.utils.formats 0.017 ms (0.01%)

ddtrace.internal.compat 0.017 ms (0.01%)

The following import paths have shrunk:

ddtrace.auto 1.194 ms (0.44%)

ddtrace 0.644 ms (0.24%)

ddtrace.internal._unpatched 0.025 ms (0.01%)

json 0.025 ms (0.01%)

json.decoder 0.025 ms (0.01%)

re 0.025 ms (0.01%)

enum 0.025 ms (0.01%)

types 0.025 ms (0.01%)

ddtrace.bootstrap.sitecustomize 0.549 ms (0.20%)

ddtrace.bootstrap.preload 0.549 ms (0.20%)

ddtrace.internal.remoteconfig.client 0.549 ms (0.20%)

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2025-07-02 00:49:51

Comparing candidate commit 0f344d970f0f77832fda7636ec3586960933a10c in PR branch vparfait/update_unicode_compat with baseline commit 44c505b078dae61d5c240e2463f75a4bebfe7db3 in branch main.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 567 metrics, 4 unstable metrics.

scenario:telemetryaddmetric-1-distribution-metric-1-times

• 🟥 execution_time [+304.478ns; +380.554ns] or [+10.476%; +13.093%]