* Use Guid.Equals(Guid) instead of the == override
* Ban the usage of Guid.Equals(Object) to prevent accidental boxing
* Compare to default(Guid) instead of Guid.Empty
when `ProviderManager.SaveMetadata` gets called before
`ProviderManager.AddParts`
```
Error Message:
System.ArgumentNullException : Value cannot be null. (Parameter 'source')
Stack Trace:
at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Linq.Enumerable.Where[TSource](IEnumerable`1 source, Func`2 predicate)
at MediaBrowser.Providers.Manager.ProviderManager.SaveMetadata(BaseItem item, ItemUpdateType updateType, IEnumerable`1 savers) in D:\a\1\s\MediaBrowser.Providers\Manager\ProviderManager.cs:line 674
at MediaBrowser.Providers.Manager.ProviderManager.SaveMetadata(BaseItem item, ItemUpdateType updateType) in D:\a\1\s\MediaBrowser.Providers\Manager\ProviderManager.cs:line 655
at Emby.Server.Implementations.Library.LibraryManager.RunMetadataSavers(BaseItem item, ItemUpdateType updateReason) in D:\a\1\s\Emby.Server.Implementations\Library\LibraryManager.cs:line 2012
at Emby.Server.Implementations.Library.LibraryManager.UpdateItemsAsync(IReadOnlyList`1 items, BaseItem parent, ItemUpdateType updateReason, CancellationToken cancellationToken) in D:\a\1\s\Emby.Server.Implementations\Library\LibraryManager.cs:line 1970
at Emby.Server.Implementations.Library.LibraryManager.CreateRootFolder() in D:\a\1\s\Emby.Server.Implementations\Library\LibraryManager.cs:line 775
at Emby.Server.Implementations.Library.LibraryManager.get_RootFolder() in D:\a\1\s\Emby.Server.Implementations\Library\LibraryManager.cs:line 180
at Emby.Server.Implementations.IO.LibraryMonitor.Start() in D:\a\1\s\Emby.Server.Implementations\IO\LibraryMonitor.cs:line 135
at Emby.Server.Implementations.IO.LibraryMonitorStartup.RunAsync() in D:\a\1\s\Emby.Server.Implementations\IO\LibraryMonitorStartup.cs:line 26
at Emby.Server.Implementations.ApplicationHost.StartEntryPoints(IEnumerable`1 entryPoints, Boolean isBeforeStartup)+MoveNext() in D:\a\1\s\Emby.Server.Implementations\ApplicationHost.cs:line 541
at System.Threading.Tasks.Task.WhenAll(IEnumerable`1 tasks)
at Emby.Server.Implementations.ApplicationHost.RunStartupTasksAsync(CancellationToken cancellationToken) in D:\a\1\s\Emby.Server.Implementations\ApplicationHost.cs:line 525
at Jellyfin.Server.Integration.Tests.JellyfinApplicationFactory.CreateServer(IWebHostBuilder builder) in D:\a\1\s\tests\Jellyfin.Server.Integration.Tests\JellyfinApplicationFactory.cs:line 101
at Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory`1.EnsureServer()
at Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory`1.CreateDefaultClient(DelegatingHandler[] handlers)
at Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory`1.CreateDefaultClient(Uri baseAddress, DelegatingHandler[] handlers)
at Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory`1.CreateClient(WebApplicationFactoryClientOptions options)
at Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory`1.CreateClient()
at Jellyfin.Server.Integration.Tests.OpenApiSpecTests.GetSpec_ReturnsCorrectResponse() in D:\a\1\s\tests\Jellyfin.Server.Integration.Tests\OpenApiSpecTests.cs:line 26
--- End of stack trace from previous location ---
```
If the lookup fails (due to a bad id in an nfo file for example), then
we had no indication of which directory failed, so the user can not
fix the problem.
Now we include the path in the error message such as:
MediaBrowser.Providers.TV.SeriesMetadataService: Error in
DummySeasonProvider for /media/x/y/z
and
MediaBrowser.Providers.Manager.ProviderManager:
TvdbSeriesImageProvider failed in GetImageInfos for type Series at
/media/x/y/z
