[Spec] UI Delay during ISettings initialization

UI Delay during ISettings initialization

• Status: Draft
• Author(s): Kartheek Penagamuri

Issue

8675 - UI delay while initializing NuGet.Configuration.ISettings type

Problem Background

VS IDE customer experiences UI Delay since NuGet tries to initialize NuGet.Configuration.ISettings (Lazy type) in the constructor of VsPackageSourceProvider type on the main UI thread.

* MEF parts are not supposed to have any thread affinity, so moving the realization of exports to a background thread can move all the disk I/O from assembly loads, JIT time, and other non-UI code to a background thread and could dramatically reduce the UI delay.
* Moving the heavyweight code that’s in the MEF activation path out of that path and into other methods that can be made asynchronous.```

## Who are the customers

All VS IDE customers

## Solution

## Implementation