Upcoming capability changes needed to support .NET 6

[jkasten2]

Summary

.NET 6 is making breaking changes which require changes to support:

In order to fully support the new native types in C# (nint, nuint), we’ve unfortunately realized that we can’t keep compatibility with existing code or assemblies built for Xamarin.iOS or Xamarin.Mac.
dotnet/macios#13087

Calling this out as a heads up for a early warning, things are still in the early stages for Xamarin with Android and iOS.

Details

The consequences are as follows when upgrading a project to .NET 6:

1. All code must be recompiled to support .NET 6. Existing assemblies (such as NuGets built for the old TargetFrameworkIdentifier xamarinios10) won’t work and won’t be supported. Non-xamarin specific assets for net4.x, netstandard, netcoreapp, net5.0+, etc. will work fine however.
2. Existing code might need to be modified. We’ll post a more detailed document with examples of code changes that might be required at a later point.

dotnet/macios#13087

Next Steps

There is a preview for iOS support with .NET 6 out but things are still in early stages.

• [Meta] .NET 6 Support dotnet/macios#8955

There isn't a migration guide yet (dotnet/macios#13087 (comment)) so it would be time efficient to wait until we have more details.

[jkasten2]

Closing this in favor of #281 since it has more activity.