HttpFileSystemBasedFindPackageByIdResource.ConsumeFlatContainerIndexAsync allocates significantly more than necessary

[ToddGrun]

NuGet Product Used

Other/NA

Product Version

VS 17.14

Worked before?

No response

Impact

It bothers me. A fix would be nice

Repro Steps & Context

This method accounts for 14% of all VS allocations in the CSharpEditingTests.ScrollingAndTyping speedometer test from VS startup until the first C# file is opened.

There are a couple behaviors that can be improved in this area.

1. Use System.Text.Json for serialization instead of NewtonSoft
2. PackageInfo.ContentUri is very infrequently used and is the cause of a large amount of allocations (I see it requested in < 0.1% of PackageInfo objects created). Defer calculation of this string until it's needed.

Below are highlighted the allocations which I think can be greatly reduced / removed

Verbose Logs