Provide an example for how sampling based on the context of the activity links could work in OTel.NET

[kalyanaj]

Feature Request

Is your feature request related to a problem?
It will be good to show an example sampler for how we can achieve more consistent sampling across linked traces. The parent based sampler mechanism provides complete traces. However, certain scenarios such as a producer-consumer scenario can be modelled using linked
activities across multiple traces. When an activity (span) links to one or more activities in other traces, the sampling decision for such linked activities would have been taken independently.

Describe the solution you'd like:
I am creating a PR for an example of a composite sampler that shows how can we achieve more complete traces across linked traces.

Describe alternatives you've considered.

Which alternative solutions or features have you considered?
None

Additional Context

This also relates to the discussion in open-telemetry/opentelemetry-specification#2918.