Review types passed to metrics tags

[JamesNK]

Metrics tags sometimes have enum and integer values. Value types always box because tags are stored as KeyValuePair<string, object?>. In some places, we avoid boxing with a cached collection of boxed values.

Note that OTel semantic conventions specify the tag type in some places, such as the HTTP status code is an integer.

Review with metrics experts to ensure we're doing the right thing.

Options

• Keep passing value types and cache value types on hot path metrics.
• Convert values to a string before passing to metrics, and rely on built-in caching. For example, Int32.ToString() and Enum.ToString() have some level of caching. The downside is that listeners may need to convert the string value back to its original type to use it.

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[joperezr]

@JamesNK is there anything left we have to do here?