We have this issue open in OpenTelemetry .NET: open-telemetry/opentelemetry-dotnet#3290

The spec says the SDK should always create a span / Activity (even when it isn't being sampled) but we don't currently do that because we feel like the GC pressure will be too high.

Opening this issue primarily because I don't think this has been tracked anywhere.

Random ideas...

• [API Proposal]: System.Diagnostics.ActivityContext.Current ability or similar #86966 has an idea to detach the context from the Activity. I think the goal is different but perhaps something like that might help.
• Perhaps we could move the data kept on Activity to a sub-class which is only instantiated when needed to lower the footprint of Activity itself.
• Some kind of pooling? Tricky because an Activity instance may be kept around for a while before it is exported (batching).

/cc @alanwest @cijothomas @utpilla