[memory management] investigate possible usage of System.IO.Pipelines in openMCDF API

[michaelp]

The following is a list of relevant resources, that IMO applicable to the current situation

1. System.IO.Pipelines: High performance IO in .NET
2. Also Span
3. and obviously [post1] (https://blog.marcgravell.com/2018/07/pipe-dreams-part-1.html)
4. [post2] (https://blog.marcgravell.com/2018/07/pipe-dreams-part-2.html)

[jeremy-visionaid]

@michaelp I'm too not sure about how applicable Pipelines would be to CFB, since it's more random access data than it is streaming... As part of v3 in #194 I've rewritten things to be mostly based around enumerators with some caching, and added support for reading/writing Spans. It reduce the memory usage to just a few KB and mostly obtains better performance than the native COM based implementation.

[jeremy-visionaid]

I'm hopeful that 3.0.0-preview1 should get released to NuGet in the next few days. @ironfede has kindly granted me write access to the repo, so I'll go ahead and close this one as fixed by #194.