After nearly going nuts, I successfully ported the library to C# and I must say that the performance remained pretty good.
All the 300 tests are successfully passing in 0:00.107 milliseconds.
I believe this is the first public port to C#, so I thought was good to share here.
If someone is interested, here is the link of the project:
By the way, my thanks for the authors for the high code quality... is quite impressive!
best wishes
Gustavo K.