GitHub pane causes performance warning banner

[jcansdale]

• GitHub Extension for Visual Studio version: 2.4.4 (dev)
• Visual Studio version: 2017

1. Install the ClearMEFComponentCache extension:
   https://marketplace.visualstudio.com/items?itemName=MadsKristensen.ClearMEFComponentCache
2. Open Visual Studio 2017
3. Show the GitHub pane (Show > Other Windows > GitHub)
4. Clear the MEF cache (Tools > Clear MEF Component Cache...)
5. Restart Visual Studio and watch for the banner
6. Click on the Manage Visual Studio Performance link

Note how many seconds were added on average. Coincidentally this is around the time it takes to construct the MEF cache. 🤔

This is related to, but different from:

• Extension likely caused X seconds of unresponsiveness Extension likely caused X seconds of unresponsiveness #1516