This project was an experimental library for ASP.NET Core, as an initial out-of-band library and exploration of concepts and a way to get feedback.
Therefore, this is replaced by ASP.NET Core 2.2 (GA around end of 2018) with official Health Checks components here: https://github.com/aspnet/Diagnostics/tree/release/2.2/src
Check the ASP.NETCore 2.2 roadmap: aspnet/Announcements#307