HttpClient slow performance on windows and linux

Hi guys,

I've noticed that httpclient is performing very slow in dotnet core comparing to golang for example.

For tests I've used VM with 16 virtual cores, and 24Gb of ram based on Intel Xeon E312 2.6Mgz

Tried windows server 2012 and centos 7.2

Code is super simple (you may find it in attached file).
And my test was made via "wrk -c 256 -t 32 http://:5000/ --latency"

Results are very upset.
On this powerful VM dotnet core httpclient performance was about 16 000 reqs/sec on windows and 12 000 reqs/sec on linux.

At the same time solution based on "golang" (check attacked file) shows results like 44 000 reqs/sec

Could you please advice what could be wrong with donet core based solution ?

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