# Description
Replace the four stack-owned `System.Diagnostics.Tracing.EventSource`
providers with source-generated `ILogger` logging.
- Preserve the legacy provider category names, numeric event IDs, event
names, levels, message structure, and semantic structured fields.
- Remove `ClientTraceFlags.EventLog` and route `ClientTraceFlags.Log`
through the canonical `OPC-UA-Core` compatibility events.
- Keep ChannelManager activities and metrics while moving its diagnostic
events to the `Opc.Ua.ChannelManager` logger category.
- Replace EventListener-based unit and stress-test collection with
structured logger providers.
- Document the ETW removal, retained compatibility identities, and
migration path for existing consumers.
## Validation
- `dotnet build UA.slnx -c Release -p:CustomTestTarget=net10.0
-p:NuGetAudit=false`
- Focused Core, Client, and Server logging tests on `net10.0` and
`net48`
- Stress harness Release build and
`SessionRecoversFromAcceptButStallAsync`
- Direct AOT test application: 115 tests passed
- `dotnet test UA.slnx -c Release -p:CustomTestTarget=net48
-p:NuGetAudit=false`
The full `net10.0` `dotnet test UA.slnx` invocation is currently blocked
by the repository's existing mixed VSTest/Microsoft.Testing.Platform
configuration in `Opc.Ua.Aot.Tests`; the AOT project builds and its test
executable passes directly.
## Related Issues
- Related to #1262
## Checklist
- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
---------
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: b0d90b8a-cde9-4fca-9a75-84f4cecb227d
Marc Schier