From a reddit thread:
I'm developing a .NET application against Hyper as a REST service and found that all my requests were taking around 350ms. Even no-op request. The solution turned out to be the dreaded 100-Continue that .NET sends by default. This can easily be disabled by setting ServicePoint.Expect100Continue to false on your WebRequest. With that change, no-op requests to the local host were on average 0ms.
From a reddit thread: