DEBUG-3700 Remove duplicated classes from Telemetry transport

[p-datadog]

What does this PR do?

Removes duplicated Core classes from Telemetry transport code.

Motivation:
As part of getting telemetry working for dynamic instrumentation, telemetry needs to work with UDS which is what shopist uses. Currently Telemetry only supports HTTP. Using the Core transport code will bring UDS transport to Telemetry.

Change log entry

Yes: Improve telemetry transport. Customers using datadog-ci-rb and webmock will need to update datadog-ci-rb to version 1.17.0 or later.

Additional Notes:

This is the first PR of a series. the next one will add a Core-based transport. This PR should be quick to review and conceptually it is standalone.

How to test the change?
Existing unit tests

I also ran datadog-ci-rb 1.15.0 tests against this PR.

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2025-04-10 17:30:19 UTC}

[datadog-datadog-prod-us1]

Datadog Report

Branch report: telemetry-transport
Commit report: 53466ae
Test service: dd-trace-rb

✅ 0 Failed, 20773 Passed, 1462 Skipped, 3m 46.65s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-04-29 18:20:35

Comparing candidate commit 53466ae in PR branch telemetry-transport with baseline commit 1b96ec8 in branch master.

Found 1 performance improvements and 0 performance regressions! Performance is the same for 30 metrics, 2 unstable metrics.

scenario:tracing - Propagation - Trace Context

• 🟩 throughput [+3811.871op/s; +3918.856op/s] or [+11.237%; +11.552%]

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.72%. Comparing base (1b96ec8) to head (53466ae).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4575      +/-   ##
==========================================
- Coverage   97.73%   97.72%   -0.02%     
==========================================
  Files        1415     1409       -6     
  Lines       86247    85968     -279     
  Branches     4359     4352       -7     
==========================================
- Hits        84293    84010     -283     
- Misses       1954     1958       +4     

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[p-datadog]

datadog-ci-rb uses one of the removed clasess thusly:

          begin
            require "datadog/core/telemetry/http/adapters/net"

            # patch gem's telemetry transport layer to use Net::HTTP instead of WebMock's Net::HTTP
            Core::Telemetry::Http::Adapters::Net.include(CI::Transport::Adapters::TelemetryWebmockSafeAdapter)
          rescue => e
            Datadog.logger.warn("Failed to patch Datadog gem's telemetry layer: #{e}")
          end

LoadError is not derived from StandardError and will escape the rescue above.

I will put back the file with a dummy class definition.

[anmarchenko]

Correction for the changelog entry as 1.16.0 is the current version:

Customers using datadog-ci-rb and webmock will need to update datadog-ci-rb to version 1.17.0 or later.

[anmarchenko]

I tested this branch together with fixes from DataDog/datadog-ci-rb#309 using Test Optimization integration tests:

https://gitlab.ddbuild.io/DataDog/apm-reliability/test-environment/-/pipelines/63750300

The tests passed:

[Strech]

LGTM