Capture request body in ASP.NET Core

[gregkalapos]

Trigger by this comment.

In #134 we added the Request.Body field, but that is only utilized by API tests, so the only way to use it is to manually set the request body.

Other agents have a setting for this. E.g. see here.

We should add this config setting and extend our ASP.NET Core instrumentation to behave accordingly.

[SergeyKleyman]

@gregkalapos Should we open a separate issue for .NET Framework?

[gregkalapos]

@gregkalapos Should we open a separate issue for .NET Framework?

Yeah, we can do that. I don't see it super important at this point though.

[katzdan]

I'll start working on this and report here.

[gregkalapos]

Implemented by @katzdan in #402