Api-diff between 7.0-preview6 and 7.0-preview7

[carlossanlop]

If you see unusual diffs in this PR, please help fixing it by offering suggestions. I would greatly appreciate it.

Notes:

• APIs that have diffs and are decorated with attributes, are getting the attribute included in the diff.
• Cci is not letting me ignore the AsyncStateMachineAttribute attribute, unlike other attributes.

ASP.NET: https://github.com/orgs/dotnet/teams/aspnet-api-review

WinForms: @merriemcgaw @RussKie @JeremyKuhne

WPF: @singhashish-wpf and @pchaurasia14

Libraries: @danmoseley @jeffhandley @karelz @ericstj @stephentoub

System.Formats.Tar @dotnet/area-system-io @carlossanlop @dotnet/area-system-io @dotnet/area-system-linq System.Net @dotnet/ncl @dotnet/area-system-numerics @dotnet/area-system-reflection-metadata System.Runtime.InteropServices @dotnet/interop-contrib @dotnet/area-system-runtime-intrinsics System.Versioning @dotnet/area-system-runtime @buyaa-n @dotnet/area-system-security @dotnet/area-system-text-json @dotnet/area-system-text-regularexpressions @dotnet/area-system-threading-tasks @dotnet/area-system-xml System @dotnet/area-system-runtime