[Experiment]Expose coverlet.core.dll as nuget package

[MarcoRossignoli]

Tackle #212

At the moment we can use coverlet in two main scenario:

• Classic coverage tool, workflow :

1. run instrumentation
2. run code
3. get coverage data

• Real time coverage analysis

1. run instrumentation
2. inject coverlet inprocess and read real time coverage data
3. get coverage data or simply close

You can checkout this branch and I did a complete working sample under Documentation/Examples/StandaloneUsage you can follow Readme.md in same folder to test by yourself.
Let me know if you're in trouble and if the api would be better.

cc possible interested guys @ppumkin @shargon @singhsarab @jnovick @vagisha-nidhi @acesiddhu @karanjitsingh @sharwell

cc: @tonerdo @petli

Video sample https://twitter.com/MarcoRossignoli/status/1201546945589841922

[petli]

Looks good, just one thought about controlling the lifetime of instrumented files.

[petli]

Could this be IDisposable instead and clean up the instrumented files on dispose? It would let the calling code control when it happens instead of it being done on process exit.

[MarcoRossignoli]

clean up the instrumented files

You mean "restore non instrumented ones"?

[petli]

Yes :)

[MarcoRossignoli]

Could be possible...I need to check how much code update...but I think that we could inject a slighly different instrumenterhelper that doesn't fire restore on process exits, I'll take a look, thank's.
This could be good also for "fire and forget" instrumentation, where we don't mind about dirty asm on target dir, and instrumentor process can die after instrument.

[petli]

The latter is also a good tool to look at instrumented files themselves. Could be an enum on InstrumenterOptions when calling ICoverageEngineFactory.CreateEngine:

enum RestoreInstrumentedModules
{
       OnProcessExit,
       OnEngineDispose,
       Never
 }

It would mean that ICoverageEngine still need to be IDisposable, even if it is only cleans up resources in some cases.

[MarcoRossignoli]

I'll try to add this feat.

[MarcoRossignoli]

Closing for now, we'll take some inspiration in future when we'll decide to expose instrumentation engine.