App Metrics
App Metrics is an open-source and cross-platform .NET library
... types to measure things such as the rate of requests, counting the number of user logins over time, measuring the time taken to execute a database query, measuring the amount of free memory, and so on. Metrics types supported are Apdex, Gauges, Counters, Meters, Histograms, and Timers. Support Push and Pull based metrics collection via TSDB-specific reporting extensions and exposing metrics in the required format over HTTP.