[Asp.Net Core, HttpClient] Clarify Enrich callback sequence

[vishweshbankwar]

Fixes # Design discussion issue #

Changes

Adding some clarification on sequencing. This is a commonly asked question/issue.

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)

[cijothomas]

@vishweshbankwar Could you do a similar doc fix for Filter, to call out the Sampling vs Processor vs FilterCallback order?

[vishweshbankwar]

@vishweshbankwar Could you do a similar doc fix for Filter, to call out the Sampling vs Processor vs FilterCallback order?

@cijothomas - We do clarify the sequence of filter versus sampler in the doc. For processor, I think its slightly more complex as that requires some explanation on what could happen to E2E trace if the span is filtered at later stage. I am thinking to clarify it here first: https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/docs/trace/extending-the-sdk/MyFilteringProcessor.cs.