Use IExternalScopeProvider for logging scopes

[epawlik]

The default logger factory can provide a scope implementation via the ISupportExternalScope and IExternalScopeProvider interfaces.

For reference, see:
Microsoft.Extensions.Logging/LoggerFactory.cs and Microsoft.Extensions.Logging/LoggerFactoryScopeProvider.cs

This gets you features like dotnet/runtime#34305 when using the default logger factory instance.

Can support be added for ISupportExternalScope and IExternalScopeProvider?

[mattwcole]

Hi, apologies for the delay getting back to you. This looks useful, thanks. If you would like support added sooner rather than later feel free to put up a pull request, otherwise I'll take a look when I have some time.

[MichalSznajder]

Just for reference: this relates to getting SpanId, TraceId, ParentId fields in your logs.

[MichalSznajder]

FYI Probably it should be possible to fake it with approach from serilog/serilog-aspnetcore#207 (comment) and adding mentioned field in when AdditionalFieldsFactory() is called.

[mattwcole]

I finally got around to adding support for this, use v2.3.0-pre2 to give it a try.