Initial implementation of stateful CBOR writer and reader classes

[eiriktsarpalis]

Contributes to #32046 and #32047.

This is an initial, prototype-grade implementation of stateful CBOR reader and writer types.

• It currently only supports four major types of the format:
  • positive & negative integers,
  • definite-length byte strings and
  • definite-length utf8 encoded strings.
• The CborWriter and CborReader types are simplistically modeled after the equivalent Asn1 implementations in the same project.
• I've added a few unit tests using example values from the CBOR spec, as well as a few property-based tests for the sake of introducing entropy in tested values.
• I've skipped concerns such as xml docs and resource strings for error messages, for now.

[bartonjs]

What's here looks reasonable, modulo either testing or removing the TryRead methods for the integer types.

I'm trying to rediscover how to get a test coverage report to include the test assembly, but the obvious things are eluding me.

[bartonjs]

I'm trying to rediscover how to get a test coverage report to include the test assembly, but the obvious things are eluding me.

The best I've come up with so far:

dotnet msbuild /t:BuildAndTest /p:Coverage=true /p:AssemblyBeingTested=System.Security.Cryptography.Encoding.Tests /p:ForceRunTests=true

Then edit the runtests.bat that's generated and add --include-test-assembly to the call to coverlet.

I don't see an obvious way to get that into the command sequence built from https://github.com/dotnet/runtime/blob/master/eng/testing/coverage.targets; though I would have sworn it used to be. Maybe I'm just not being clever enough.

[eiriktsarpalis]

Test failures are all System.Reflection and System.Runtime.Loader related.

[eiriktsarpalis]

Then edit the runtests.bat that's generated and add --include-test-assembly to the call to coverlet.

Do you think it might make sense to move to the main project and keep types internal?