Fixes and speed up for .NET Core sample

[ForNeVeR]

On my Windows machine, this improved the performance of .NET Core sample more that twice (from 11k RPS to 24k RPS). Although my current computational environment is very unstable. I'd be happy to hear your results.

Thanks.

[ju-bear]

ASP.NET Core is capable to handle requests by either using Controllers or using request handlers as in your example. Spring Boot service in this benchmark uses RestController to handle requests.

Maybe 2 separate versions of .NET Core service should be made? One that uses Controllers without any MVC-specific features and another that handles the request directly?

[Ubloobok]

@dredd92 it's a great idea about 2 versions for .NET Core, it'll be more correct for demonstration.

[ForNeVeR]

Superseded by #16.