Fixed Sentry SDK has not been initialised when using ASP.NET Core, Serilog and OpenTelemetry

[jamescrosswell]

Resolves #2738

Problem

When using Sentry in an ASP.NET Core application, using SeriLog for logging and OpenTelemetry for tracing, the SentrySpanProcessor would throw an exception:

sentry-dotnet/src/Sentry.OpenTelemetry/SentrySpanProcessor.cs

Lines 44 to 46 in 84925a9

	throw new InvalidOperationException(
	"The Sentry SDK has not been initialised. To use Sentry with OpenTelemetry tracing you need to " +
	"initialize the Sentry SDK.");

Solution

When the logging backend is replaced by SeriLog, SentrySdk.CurrentHub doesn't get initialized until after TracerProviderBuilderExtensions.AddSentry gets run. I don't fully understand all the mechanics, to be honest - as far as I can tell, our ConfigureLogging code does actually get called, then it gets nuked by the SeriLog initialization, and finally our SDK gets initialized in by the SentryStartupFilter.

In any event, retrieving an IHub from DI rather than pulling it off the SentrySdk static class ensures we are always able to resolve this (regardless of whether the MEL backend has been replaced or not).

I'd love a better explanation of what's going on here, if anyone else can provide one.

Backport

• Fixed Sentry SDK has not been initialised  #2918