[WCF] Avoid creating activity

[martincostello]

Changes

Avoid creating an activity and associated tags if there are no trace listeners configured for the activity source.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.18%. Comparing base (d074a71) to head (4651661).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5124   +/-   ##
=======================================
  Coverage   78.18%   78.18%           
=======================================
  Files         484      484           
  Lines       20555    20559    +4     
=======================================
+ Hits        16071    16075    +4     
  Misses       4484     4484           

Flag	Coverage Δ
unittests-Instrumentation.Wcf	82.72% <100.00%> (+0.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...Wcf/Implementation/ClientChannelInstrumentation.cs	88.88% <100.00%> (+0.20%)	⬆️
...mplementation/TelemetryDispatchMessageInspector.cs	93.20% <100.00%> (+0.13%)	⬆️

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[Copilot]

Pull request overview

Optimizes WCF tracing by skipping activity tag construction when the selected activity source has no listeners.

Changes:

• Adds listener checks for incoming server requests.
• Adds listener checks for outgoing client requests.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
TelemetryDispatchMessageInspector.cs	Adds the incoming-request fast path.
ClientChannelInstrumentation.cs	Adds the outgoing-request fast path.

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Pull request dashboard status

Waiting on reviewers · refreshed 2026-08-26 19:56 UTC

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