Top corefxlab issues

Create core geometry, drawing and imaging libraries

Add a generic OrderedDictionary class

area-System.Collections

ArrayElementReference<T> variant of the new Span<T> / Memory<T>

OpenBeforeArchiving area-System.Memory

Resolve un-contiguous memory into contiguous memory

area-System.Buffers enhancement

WritableBuffer / OutputWriter / IOutput: Combine the Ensure() method and Span property; possibly rename to `GetSpan`

Support appending foreign buffers to pipe

area-System.IO.Pipelines enhancement

Move Buffer<T> and friends to corlib, netstandard, system.runtime

area-System.Memory scheduled

JsonReader does not handle escaped quotes in strings

area-System.Text.Json

Beyond matrix operations.

OpenBeforeArchiving area-Other enhancement

Proposal for native int (nint)

OpenBeforeArchiving area-Other design