Marc Alff

@tashivani Thanks for the detailed report. The build logs (found in the vcpkg issue) indicate: ``` -- OPENTELEMETRY_VERSION=1.12.0 ``` vcpkg has been updated already: * https://github.com/open-telemetry/opentelemetry-cpp/pull/2412 and this fix is...

Bonjour @nleclercq The span `End()` method can take a `EndSpanOptions` parameter. Keeping a pointer on the span to call End() allows to pass `EndSpanOptions`. Most of the time, end span...

Instead of a Scope::Span() method, the following is preferred: ``` { ... // start span with parent context extracted from http header auto span = get_tracer("http-server")->StartSpan(span_name, {}, options); // make...

> If I remember correctly, Async export was put under feature flag as it is not specs compliant. It calls Export::export simultaneously without waiting for previous call to end. Good...

To summarize: * HTTP async is in the spec, and implemented * GRPC async is in the spec, but not implemented * the name `WITH_ASYNC_EXPORT_PREVIEW` is not specific to HTTP...

Thanks for the heads up. On hold for now, waiting for the spec and proto to be updated: * https://github.com/open-telemetry/opentelemetry-specification/issues/3411 * https://github.com/open-telemetry/opentelemetry-proto/pull/503

So: * this is a recent addition in the spec, * the meter API is impacted, as it needs a new virtual method, * this makes it an ABI breaking...

Depends on: * https://github.com/open-telemetry/opentelemetry-cpp/pull/2224 which will add CI for a WITH_ABI_VERSION_2 build.

Adding the breaking change label: this will require a new or changed API, hence changing the API ABI for metrics.

@lalitb After `AddCallback()` is called, the `ObservableRegistry` contains a back pointer to the instrument. I think that what is missing here, is cleanup in the `ObservableInstrument` destructor to remove back...