Align messaging diagnostics

[PascalSenn]

No description provided.

[Copilot]

Pull request overview

This PR refactors Mocha’s messaging diagnostics from a single IBusDiagnosticObserver to a listener-based model (IMessagingDiagnosticEventListener / IMessagingDiagnosticEvents) that supports multiple registered listeners and aligns error-path signaling across dispatch/receive/consume.

Changes:

• Replace IBusDiagnosticObserver with IMessagingDiagnosticEvents and listener/aggregation infrastructure.
• Update dispatch/consume instrumentation middlewares to emit error events on exceptions.
• Update tests and the OpenTelemetry example to use the new diagnostic listener registration APIs.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/Mocha/test/Mocha.Tests/Middlewares/Receive/ReceiveInstrumentationMiddlewareTests.cs	Updates tests to use IMessagingDiagnosticEvents and renamed error callback expectations.
src/Mocha/test/Mocha.Tests/Middlewares/Dispatch/DispatchInstrumentationMiddlewareTests.cs	Updates tests to use IMessagingDiagnosticEvents.
src/Mocha/test/Mocha.Tests/Middlewares/Consume/ConsumerInstrumentationMiddlewareTests.cs	Updates tests to use IMessagingDiagnosticEvents.
src/Mocha/src/Mocha/Observability/NoOpBusDiagnosticObserver.cs	Removes old no-op observer implementation.
src/Mocha/src/Mocha/Observability/IBusDiagnosticObserver.cs	Removes old observer interface.
src/Mocha/src/Mocha/Observability/Configuration/InstrumentationBusExtensions.cs	Adds listener registration APIs (AddDiagnosticEventListener) and updates AddInstrumentation().
src/Mocha/src/Mocha/Middlewares/Receive/ReceiveInstrumentationMiddleware.cs	Switches receive instrumentation to IMessagingDiagnosticEvents.
src/Mocha/src/Mocha/Middlewares/Dispatch/DispatchInstrumentationMiddleware.cs	Switches to IMessagingDiagnosticEvents and adds dispatch error callback on exception.
src/Mocha/src/Mocha/Middlewares/Consume/ConsumerInstrumentationMiddleware.cs	Switches to IMessagingDiagnosticEvents and adds consume error callback on exception.
src/Mocha/src/Mocha/Instrumentation/NoopMessagingDiagnosticEvents.cs	Introduces no-op diagnostics implementation for the new model.
src/Mocha/src/Mocha/Instrumentation/MessagingDiagnosticEventListener.cs	Adds a base class with no-op defaults and a shared empty scope.
src/Mocha/src/Mocha/Instrumentation/IMessagingDiagnosticEvents.cs	Introduces the new diagnostics events interface used by middlewares.
src/Mocha/src/Mocha/Instrumentation/IMessagingDiagnosticEventListener.cs	Introduces the listener interface (multiple implementations supported).
src/Mocha/src/Mocha/Instrumentation/AggregateMessagingDiagnosticEvents.cs	Adds aggregation over multiple listeners, returning an aggregate scope.
src/Mocha/src/Mocha/Instrumentation/ActivityMessagingDiagnosticListener.cs	Replaces prior OpenTelemetry observer with an Activity-based listener implementation.
src/Mocha/src/Mocha/Builder/MessageBusBuilder.cs	Resolves listeners and selects no-op/single/aggregate diagnostics for runtime.
src/Mocha/src/Examples/Observability/OpenTelemetry/OpenTelemetryExample.cs	Updates example to register instrumentation + a custom listener via the new APIs.

Comments suppressed due to low confidence (1)

src/Mocha/src/Mocha/Instrumentation/ActivityMessagingDiagnosticListener.cs:7

• This change replaces the previously public OpenTelemetry diagnostic observer type with an internal listener (ActivityMessagingDiagnosticListener). If OpenTelemetryDiagnosticObserver was part of the public surface area, this is a breaking change for consumers who referenced it directly. Consider keeping a public, obsolete shim type (forwarding to the new listener model) or documenting the migration path in release notes.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (7c63577) to head (1d9dc97).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #9488   +/-   ##
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