UI Delay - [PerfWatson] UIDelay: microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.Invoke|nuget.visualstudio.implementation.dll!NuGet.VisualStudio.PumpingJTF.WaitSynchronously

[nkolev92]

There's a UI delay happening when the editor suggests a package to be installed.

There are 2 obvious issues here:

1. We have a synchronous API which blocks the calling thread.
2. We are being invoked on the UI thread, which we can't blame others for because frequently IVS sync APIs are invoked on the UI thread.

The correct solution here is an async VS Package Installer service.

microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.Invoke	91.8%
microsoft.visualstudio.languageservices.dll!Microsoft.VisualStudio.LanguageServices.Implementation.Utilities.VisualStudioWaitIndicator.Wait	91.4%
microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction+<>c__DisplayClass_0.b__	91.4%
microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.InnerInvoke	91.4%
microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.InvokeCore	91.4%
microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction+<>c__DisplayClass_0.b__	91.4%
microsoft.codeanalysis.editorfeatures.wpf.dll!Microsoft.CodeAnalysis.Editor.Implementation.Suggestions.SuggestedAction.InvokeWorker	91.2%
microsoft.codeanalysis.editorfeatures.dll!Microsoft.CodeAnalysis.Editor.Implementation.CodeActions.CodeActionEditHandlerService.Apply	76.8%
microsoft.codeanalysis.editorfeatures.dll!Microsoft.CodeAnalysis.Editor.Implementation.CodeActions.CodeActionEditHandlerService.ProcessOperations	76.6%
microsoft.codeanalysis.features.dll!Microsoft.CodeAnalysis.AddImport.AbstractAddImportFeatureService`+InstallPackageAndAddImportOperation[System.__Canon].TryApply	74.8%
microsoft.codeanalysis.features.dll!Microsoft.CodeAnalysis.AddPackage.InstallPackageDirectlyCodeActionOperation.TryApply	74.8%
microsoft.visualstudio.languageservices.dll!Microsoft.VisualStudio.LanguageServices.Packaging.PackageInstallerService.TryInstallPackage	74.8%
microsoft.visualstudio.languageservices.dll!Microsoft.VisualStudio.LanguageServices.Packaging.PackageInstallerService.TryInstallAndAddUndoAction	74.8%
microsoft.visualstudio.languageservices.dll!Microsoft.VisualStudio.LanguageServices.Packaging.PackageInstallerService.TryInstallPackage	74.8%
nuget.visualstudio.implementation.dll!NuGet.VisualStudio.VsPackageInstaller.InstallLatestPackage	67%
nuget.visualstudio.implementation.dll!NuGet.VisualStudio.VsPackageInstaller.InstallPackage

Related: #8842

Internal issue: 959448

[nkolev92]

The solution here is to not call this API on the UI thread.
However, IVS sync APIs are called from the UI thread as a pattern.

The NuGet side of the fix is: #8896
Keeping this one tracking for the partner side usage of new service.

[nkolev92]

Lots of work was already started here.

[nkolev92]

pri3 per discussions with @aortiz-msft